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72; New forms of Coryphodontidæ, 73: An anthropomorphous Lemur, 73: The Archæan Rocks

of Great Britain, 74; A new British Formation, 74; Recent extinction of the Mastodon, 74: The

Mesozoic of Virginia, 75: Geological News, 76; A new genus of Tillodonta, 156; A great de-

posit of Mud and Lava, 157; Invertebrate fossils from the Lake Valley district, New Mexico'

158; Insects of the Amyzon shales of Colorado, 159; The future of Geology, 160; Marsh on the

classification of the Dinosauria, 253; The Dinosaurs of Bernissart, 255; Hulke on Polocanthus

foxi, 256; Russian Sauropterygia, 256; The Geology of Florida, 256: Geological News, 257:

New characters of the Perissodactyla condylarthra, 334; Mesonyx and Oxyæna, 334; The rachi-

tomous Stegocephali, 334: Marsh on the Dinosauria, 335: Geological News, 335: A second

genus of Eocene Plagiaulacidæ, 416; Two new genera of the Puerco Eocene, 417; "Mud

lumps" and mounds near New Orleans, 418; Geological Notes, 423; The ancestry and habits of

Thylacoleo, 520; Notes on Eocene Mammalia, 522; On the Taxeopoda, a new order of Mamma-

lia, 522; Geological News, 523; Lesquereux on the Tertiary Flora as related to the Tertiary

Animals of the West, 602; The Geological and Natural History Survey of Canada, 602; Ab-

sence of ancient Glaciers in Eastern Asia, 654; A new genus of Tæniodonta, 604; Geological

News, 605; New Marsupials from the Puerco Eocene, 684; Geological News, 686; The South-

em Limit of Ancient Glaciers in Pennsylvania, 753; New Phyllopod and Phyllocaridan Crus-

tacea from the Devonian of New York, 754; White's Contributions to Mesozoic and Tertiary

Paleontology, 754: Whitfield's new species of Fossils from Ohio, 755; Davis on the Little

Mountains east of the Catskills, 755; Geological Notes, 755; Mammalia in the Laramie Forma-

tion, 830: A new form of Tæniodonta, 831; The Periptychidæ, 832; Some new forms from

the Puerco Eocene, 833: Geological News, 834: Theories of the Origin of the Loess, 920; The

Recent Discoveries of Fossil Footprints in Carson, Nevada, 921; Origin and Mode of Formation

of Saline Mineral Waters, 923; The so-called Leadville Porphyry, 925; Permian Vertebrata,

925: Geological News, 925; A fossil Croatian Whale (Mesocetus agrami), 1027; Origin of the

Prairies, 1028; Davis' Classification of Lake Basins, 1028; Collett's Geology of Indiana for

1881, 1028; Two new genera of Mammalia from the Wasatch Eocene, 1029; White's Carbonifer-

ous Invertebrate Fossils of New Mexico, 1029; Geological News, 1030.

Mineralogy-Systematic Mineralogy, 76; Lime crystals in a limekiln, 77; Nitrobarite, 78;

Vanadium minerals, 78; Microlite from Virginia, 79; Diadochite, 79; Vivianite, 79; Rosterite,

79: Uranothorite, 79; Beauxite, 79; Bergamaskite, 80; New Bismuth minerals, 80; The opti-

cal properties of Pyromorphite and Mimetite, 80; Chalcocite on an old coin, 80; Nova Scotia

minerals, 80; Phytocollite, a new mineral from Scranton, Pa., 161; Cossyrite, 162; Alaskaite,

162; Pseudomorphs of copper after Aragonite, 162; Electricity developed by the compression of

crystals, 162; Note on Gold, 163; A new text book of mineralogy, 163; Mineralogical News,

164: Helvite from Amelia county, Virginia, 337; A new Manganese mineral, 338; Galena with

octahedral cleavage, 338; The condition of sulphur in coal, 338; Spiral figures in crystals, 339:

Native silver, 339; Some Virginia minerals, 540; New minerals, 340; Mineralogical Notes, 341;

Pseudo-symmetry, 421; Hieratite, a new mineral, 423; Monazite from Virginia, 423; Some sup-

posed new Scottish minerals, 424; Menaccanite, Leucoxite and Titanomorphite, 424; New min-

erals, 425; Mineralogical Notes, 425; Two new guano minerals, 524: Uranothallite, 525; Chio-

hite and Chodneffite, 525; Rhodizite, 526; Crosby's Common Minerals and Rocks, 526; Martite,

826; Smaltite from Colorado, 527; New mineral resins, 527; The Sands of the Desert of Sahara,

527: Mineralogical Notes, 527: Proceedings of the Mineralogical Section of the Phila. Academy

of Natural Sciences, 607; A new locality for Hayesine, 610; The third appendix to Dana's Min-

eralogy, 610; Orthite from Virginia, 611; New Analyses of Columbite and Monazite, 611; Obit-

uary, 611; A Phosphorescent Variety of Limestone, 687; Proceedings of the Mineralogical So-

ciety of Great Britain and Ireland, 688; Lernilite and other supposed new German Minerals,

690; Minerological Notes, 690; The Manufacture of Artificial Diamonds, 756; Pyrites as a

source of Sulphuric Acid, 756; A dimorphous form of Tin, 757: Blasting with Lime, 757:

The Formation of Sulphur in the Soil of Paris, 757; Mineralogical Notes, 758; Chrome Tourma-

line, 835; Paraffine in Lava, 835; New Localities, 835; A relation between the optical and chem-

ical properties of Pyroxene and Amphibole, 836; New Minerals, 836; Diabantite-vermiculite,

836; Salt water in Sulphur Crystals, 837! The dispersion of Chromate of Soda, 837; Aluminium

as a blow-pipe support, 837; Ersbyite, 838; Mineralogical Notes, 838; The action of Heat upon

Crystals of Boracite, 926; Prehnite, 926; American Monazites, 927; Minerals from Pike's Peak,

928; Mineralogical Notes, 928; Some new minerals in Meteorites, 1031; Corundum and its Alter-

ations, 1032; The Paragenesis of Minerals, 1033; A mountain of Martite, 1034; Analyses of

Helvite, 1034-

Geography and Travels.-M. de Brazza's Journey from the Ogowe to the Congo, 80; Cen-

tral Africa, 81; Arctic Discovery, 83; International Polar Conference, 83; Geographical News ;
84: The Jeannette and the Search Expeditions, 165, Arctic Exploration, 167; Geographical

Notes, 168; Dr. Lenz on the Sahara, 258; Arctic Exploration, 259; Explorations in Equatorial

Africa, 341; The Caroline Archipelago 426; The Pamir, 427; Alaska, 427; Polar Stations.

427; Dr. Crevaux in South America, 428 African Exploration, 428; Geographical Notes, 429:

The Congo, 528; Lake Nyassa, 528; O'Neill's Journey in Makua Land, 529; Abyssinia, 530;

Schuver, 531; The new Polar Stations, 532; The Chukches and the Kuro-Sivo, 612; Geographi-

cal Notes, 612; African Exploration, 758; The Circumpolar Stations, 761; The Rescue of the

Crew of the Eira, 838; African Exploration, 839; Deep-sea Explorations, 840; Ascent of Mount

Cook, 840; Afghanistan, 840; De Brazza's Explorations on the Ogowe and the Congo, 928;

Stearns' Expedition to Labrador, 930; Proceedings of the Geographical Section of the British

Association, 1034; Pogge and Wissman, 1039; African Exploration, 1040.

Microscopy.-A hollow glass sphere as a condenser for microscopic illumination, 169; Arresta-

tion of infusorial life, 170; The Acme microscopes, 261; American Society of Microscopists,

344; Bausch's homogeneous immersion objectives, 341; Lehigh Valley Microscopical Society,

347: Pigeon-post Films, 347; Blood stains on steel, 347; The new Trichinoscope, 429; Structure

of the cotton fiber, 431; Practical microscopy, 432; Measurement of microscopic aperture,

532; A new journal, 533: Summer School of Biology, 533: Micro-chemistry, 614; Protector for

Objectives, 618; Living Objects for the Microscope, 618; The August Meetings, 691; Eye Pro-

tectors, 691; An Adjustable Spring Clip, 692; Cereal foods under the Microscope, 693; Remo-

val, 693; Microscopic Dexterity of the Cameo Cutters, 762; The Microscope in the Detection of

Forgery, 763; Kent's Infusoria, 763; Bibliography of the Microscope, 841; Apparent size of

magnified objects, 841; Double staining of nucleated Blood Corpuscles, 841; Mounting with

black Background, 842; Microscopy at the American Association, 931; Martin's Unmounted

Objects, 931; Taylor's Freezing Microtome, 1040; Relation of Aperture and Power, 1042; Visi-

bility of Fine Rulings, 1042; Cutting Sections of Coal, 1043; The House-fly as a carrier of Con-

tagion, 1044; Recent Microscopical Papers, 1044.

THE

AMERICAN NATURALIST.

VOL. XVI. JANUARY, 1882. No. 1.

THE BLIND CAVE FISHES AND THEIR ALLIES.

A

BY S. A. FORBES.

N unusual interest attaches to everything relating to the blind fishes of the caves, partly because of their peculiar deprivation and the compensation for it afforded by the development of special sensory structures more useful to them in their subterranean situation than eyes would be, and partly because the origin of their peculiarities has proved an inviting subject of speculation and discussion with reference to the doctrine of natural selection. In the careful papers of Mr. F. W. Putnam,1 especially, we find accurate descriptions of the genera and species, and a clear statement of opposing views respecting the derivation of these little fishes.

A strict evolutionist passes, perhaps too easily, from the idea of the unbroken, rayless night in which the blind fishes live and seem to have lived for ages, to that of their atrophied eyes and highly developed epidermal organs of sense-connecting these at once as cause and effect on the strength of his general theory. In papers written, one nine and the other seven years ago, Mr. Putnam presented, partly in criticism of previously published explanations of Mr. Cope, facts and considerations which seemed to him to break the force of the argument based by evolutionists upon the peculiar adaptation of the blind fishes to their surroundings, and even to compel the conclusion that the darkness of their situ

1 AMERICAN NATURALIST, January, 1872. Annual Report of the Peabody Academy of Science for 1871. Proceedings of the Boston Society of Natural History, Vol. XVII, 1874, pp. 222-225.

2 Ann. Mag. Nat. Hist., Nov., 1871.

VOL. XVI.-NO. 1

ation did not bring about the atrophy of their eyes, the develop. ment of their special organs of sense, or the bleaching of their skins.

The discussion seems not to have been carried further; and I now revive the subject because the study of a new species closely allied to the blind fishes, which has recently been discovered in Illinois, enables me to contribute a few facts which throw additional light upon it.

In the papers cited, it is argued, in brief, that the conclusions as to adaptation based upon the absence of functional eyes and the extraordinary development of tactile organs in Amblyopsis and Typhlichthys are negatived by the fact that in Chologaster, an equally subterranean genus, tactile organs are wanting, and eyes are fully developed. If genera without eyes, and another genus with them, are found living under the same conditions, the inference is obvious that the conditions cannot have caused this difference.

The possible rejoinder that Chologaster may still retain its eyes because it has had a shorter subterranean history, and has not yet become so thoroughly adapted to cave life as its predecessors, is forestalled by the argument that we have no right to assume that Chologaster is a later inhabitant of underground retreats than the blind fishes, until at least one specimen of the former has been found in the outer waters in the vicinity of the caves. The same reasoning is applied to the difference of color-Amblyopsis being colorless and Chologaster brown.

On page 232 of the NATURALIST for March, 1881, I briefly described a single specimen of Chologaster obtained by Mr. F. S. Earle from a spring in Southern Illinois; but did not undertake to decide, from a single example, whether it belonged to a distinct species or not. Seven additional specimens obtained by the same gentleman from the same place, agree so closely with the one previously found that it is evident that all belong to one species, and I have no longer any doubt that this is distinct from the two previously described,'

Chologaster papilliferus, n. s. The head is broad and flat, contained three and a-half times in the body (without caudal), widest posteriorly and broadly rounded in front. Its width between the eyes is half its length. The eye is contained about six times in the length of the head, and is placed above and behind the tip of the maxillaries. The greatest depth of the body is contained five times in its length to caudal. The pectoral fins reach only half way to the anal; and the caudal is broadly

The most important and interesting peculiarity of this species indicates a more advanced stage of adaptation to a subterranean life than that of its congeners. On all the surfaces of the head appear short rows of peculiar tubercles, relatively wider than the papillæ of Amblyopsis, but also apparently shorter. They are much the largest about the anterior nostril and on the lower jaw, and are larger on the side of the head than on its upper surface. While the papillæ of Amblyopsis are set on ridges of the skin, those of this Chologaster are somewhat sunken within it, and often placed in grooves; and it is not until they are freed from the adjacent epidermis by dissection, that their full height is seen. When thus exposed they closely resemble the papillæ of Amblyopsis in form and size, and are similarly cupped at the tip. Aver

rounded and almost truncate. The color is brown above, paler below, with three narrow longitudinal stripes, the upper and lower black, the middle one pale with narrow black edging above and below. With a glass the ground color is seen to be everywhere minutely mottled black and white. The fins are all nearly or quite concolorous, except the caudal, which is minutely marked with rows of white specks on a dusky ground. These specks indicate the articulations of the fin rays. There is usually a dusky vertical bar at base of tail. The dorsal and anal fins are thick and fleshy, their height about equal to their length, the former with six and the latter with five rays.

On all surfaces of the head, peculiar tubercles or papillæ occur in short rows, much the largest on the lower jaw and about the anterior nostril, where they are sunken in grooves of the skin. They are also larger on the side of the head than above. An irregular double row surrounds the anterior nostril, except externally, and behind this appear four short, transverse rows on each side, the last of these be. ing a little behind and within the eye. Then follow about eight short, irregularly placed, oblique and transverse rows, accompanied posteriorly by a longitudinal row. On each side of the middle of the back part of the head is a short longitudinal row, each with a small patch not far from its tip. At the upper end of the gill-slit is a conical tubercle with an apical perforation; and traces of a series of vertical rows of tubercles appear on the anterior part of the side of the body. The side of the head bears many short vertical rows, with some longitudinal and oblique rows also. On the under side of the lower jaw, a double or triple row of large papillæ is set in a groove just within the jaw, and a small, triangular, sunken patch is found a little within the anterior end of this row. Another longer row of smaller papillæ runs parallel to the former, between it and the hyoid arch. Average specimens measure 37mm. in total length.

This species presents the internal characters of the genus, as defined by Mr. Putnam in his "Synopsis of the family Heteropygii," published in the Annual Report of the Peabody Academy of Science for the year 1871. The description of the genus should be amended, however, by the omission of the statement concerning papillary ridges and an opercular papilla.

Taken from a spring at the base of a limestone bluff, in Union county, in Southern Illinois.

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