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and a species of Pycnogonum. Several of the last-named crustaceans were taken at a depth of 250 fathoms, entangled on a swab, fastened in front of a deep-sea lead, which was attached to the rope, few feet from the mouth of the dredge. This circumstance tends to show that the genus is not always parasitic in its habits. The Decapods, Amphipods, &c., at least those of greatest interest, have not yet been identified. Among the most noticeable of the marine Polyzoa are Defrancia truncata, and what appears to be a Retepora. Not many species in this group were obtained in very deep water, and those procured were, for the most part, of small size. About six species of Tunicates were collected. Being anxious to have Mr. J. Gwyn Jeffreys' opinion upon the various species of Mollusca during his visit to Montreal, I studied these carefully first, and submitted the whole of them to him for examination. Twenty-four species of Testaceous Mollusca were obtained at depths of from 90 to 250 fathoms. Nearly all of these are Arctic forms, and eleven of them are new to the continent of America.
The following are some of the most interesting of the deepwater Lamellibranchiata :-Pecta grænlandicus of Chemnitz, but not of Sowerby; * Arca pectunculoides Scacchi; Yoldia lucida Loven; Y. frigida * Torell; Neœra artica Sars; N. Obesa* Loven. Among the novelties in the Gasteropoda of the same zone are the subjoined :-Dentalium abyssorum Sars; Siphonodentalium vitreum Sars; Eulima stenostoma Jeffreys; Bela Trevelyana Turton; Chrysodomus (Sipho) Sarsii Jeffreys. Three Brachiopods occur in the Gulf, of which Rhynchonella psittacea and Terebratella Spitzbergensis are found in about 20-50 fathoms, and Terebratula septentrionalis in from 100-250. A few rare shells were obtained in comparatively shallow water; among them an undescribed Tellina (of the section Macoma), a new Odostomia, and Chrysodomus (Sipho) Spitzbergensis* Reeve. Nor were even the Vertebrata unrepresented; from a depth of 96 fathoms off Trinity Bay, a young living example of the " Norway Haddock" (Sebastes Norvegicus) was brought up in the dredge. And off Charleton Point, Anticosti, in 112 fathoms, on a stony bottom, two small fishes were also taken; one, a juvenile wolf-fish
• I am indebted to Mr. Jeffreys for the identification of species to which an asterisk is attached. He corroborates also my determination of the remainder.
(Anarrhicas lupus) the other a small gurnard, a species of Agonus, probably A. hexagonus Schneid.
The similarity of the deep-sea fauna of the St. Lawrence to that of the quaternary deposits of Norway, as described by the late Dr. Sars, is somewhat noticeable. Pennatula, Ophiura Sarsii, Ctenodiscus crispatus, several Mollusca, &c., are common to both; but on the other hand, the absence of so many charac teristic European invertebrates on the American side of the Atlantic should be taken into consideration. The resemblance between the recent fauna of the deeper parts of the St. Lawrence, and that of the Post-pliocene deposits of Canada, does not seem very close, but our knowledge of each is so limited that any generalisations would be premature.-J. F.WHITEAVES in "Nature."
FISH-NEST IN THE SEA-WEED OF THE SARGASSO SEA.Extracts from a letter from Professor Agassiz to Prof. Peirce, Superintendent U. S. Coast Survey, dated Hassler Expedition, St. Thomas, Dec. 15, 1871.-* * *The most interesting discovery of the voyage thus far is the finding of a nest built by a fish, floating on the broad ocean with its live freight. On the 13th of the month, Mr. Mansfield, one of the officers of the Hassler, brought me a ball of Gulf weed which he had just picked up, and which excited my curiosity to the utmost. It was a round mass of sargassum about the size of two fists, rolled up together. The whole consisted, to all appearance, of nothing but Gulf weed, the branches and leaves of which were, however, evidently knit together, and not merely balled into a roundish mass; for, though some of the leaves and branches hung loose from the rest, it became at once visible that the bulk of the ball was held together by threads trending in every direction, among the sea-weed, as if a couple of handfuls of branches of sargassum had been rolled up together with elastic threads trending in every direction. Put back into a large bowl of water, it became apparent that this mass of sea-weed was a nest, the central part of which was more closely bound up together in the form of a ball, with several loose branches extending in various directions, by which the whole was kept floating.
A more careful examination very soon revealed the fact that the elastic threads which held the Gulf weed together were beaded at intervals, sometimes two or three beads being close together, or a bunch of them hanging from the same cluster of
threads, or they were, more rarely, scattered at a greater distance one from the other. Nowhere was there much regularity observable in the distribution of the beads, and they were found scattered throughout the whole ball of sea-weeds pretty uniformly. The beads themselves were about the size of an ordinary pin's head. We had, no doubt, a nest before us, of the most curious kind; full of eggs too; the eggs scattered throughout the mass of the nest and not placed together in a cavity of the whole structure. What animal could have built this singular nest, was the next question. It did not take much time to ascertain the class of the animal kingdom to which it belongs. A common pocket lens at once revealed two large eyes upon the side of the head, and a tail bent over the back of the body, as the embryo uniformly appears in ordinary fishes shortly before the period of hatching. The many empty egg cases observed in the nest gave promise of an early opportunity of seeing some embryos freeing themselves from their envelope. Meanwhile a number of these eggs with live embryos were cut out of the nest and placed in separate glass jars to multiply the chances of preserving them, while the nest as a whole was secured in alcohol, as a memorial of our unexpected discovery. The next day I found two embryos in one of my glass jars; they occasionally moved in jerks, and then rested for a long while motionless upon the bottom of the jar. On the third day I had over a dozen of these young fishes in my rack, the oldest of which began to be more active, and promised to afford further opportunities for study.
* * *But what kind of fish was this? About the time of hatching, the fins of this class of animals differ too much from those of the adult, and the general form exhibits too few peculiarities, to afford any clue to this problem. I could suppose only that it would probably prove to be one of the pelagic species of the Atlantic, and of these the most common are Exocœtus, Naucratus, Scopelus, Chironectes, Syngnathus, Monacanthus, Tetraodon and Diodon. Was there a way to come nearer to a correct solution of my doubts?
As I had in former years made a somewhat extensive study of the pigment cells of the skin, in a variety of young fishes, I now resorted to this method to identify my embryos. Happily we had on board several pelagic fishes alive, which could afford means of comparison, but unfortunately the steamer was shaking too much and rolling too heavily, for microscopic observation of even moder
ately high power. Nothing however, should be left untried, and the very first comparison I made secured the desired result. The pigment cells of a young Chironectes pictus proved identical with those of our little embryos.
It thus stands as a well authenticated fact that the common pelagic Chironectes of the Atlantic (named Chironectes pictus by Cuvier), builds a nest for its eggs in which the progeny is wrapped up with the materials of which the nest itself is composed; and as these materials are living Gulf weed, the fish-cradle, rocking upon the deep ocean, is carried along as an undying arbor, affording at the same time protection and afterward food for its living freight.
This marvelous story acquires additional interest if we now take into consideration what are the characteristic peculiarities of the Chironectes. As its name indicates, it has fins like hands; that is to say, the pectoral fins are supported by a kind of prolonged, wrist-like appendages, and the rays of the ventrals are not unlike rude fingers. With these limbs these fishes have long been known to attach themselves to sea-weed, and rather to walk than to swim in their natural element. But now that we have become acquianted with their mode of reproduction, it may fairly be asked if the most important use to which their peculiarly constructed fins are put is not probably in building their nest.-Silliman's Journal.
PROF. AGASSIZ'S EXPEDITION.-It is probable that I may have been anticipated, as regards part of the present communication. If not, I believe that many of your readers will be glad to learn the objects with which Prof. Agassiz has started, with Count Pourtales and a distinguished band of skilled observers, on a scientific expedition in the United States' surveying ship Hassler, and to receive a brief account of what he has already done at St. Thomas and Barbados, at which places he was obliged to touch, in consequence of defects in the vessel or her machinery.
The Expedition was detained some days at St. Thomas, and the time of the Professor and his assistants was devoted chiefly to the collection and preparation of fishes, with a view to the study of the brain, and the breathing and digestive organs. Several boxes full, preserved in alcohol, were at once shipped to the United States, as the first-fruits of the Expedition.
The party arrived at Barbados on December 26, and spent four days there. The first two were devoted by the Professor to exa
mining and studying the large collection of West Indian shells, marine and terrestrial, of corals, sponges, crustacea, semi-fossil shells of the island, made by the Governor, Mr. RAWSON. Of the marine series he wrote in the following terms to Mr. J. G. Anthony, the Curator of the Harvard Museum:-"I am having high carnival. I have found here what I did not expect to find anywhere in the world-a collection of shells in which the young are put up with as much care as the adult, and extensive series of specimens show the whole range of changes of the species, from the formation of the nucleus to the adult." He was particularly struck with the now unique specimen of Holopus, lately procured by Mr. RAWSON, which was described by Dr. J. E. Gray in the December number of the "Annals of Natural History," and named by him, from a drawing, H. Rawsoni, but which Agassiz, who had seen the specimen of D'Orbigny in Paris, before it disappeared, considers to be a normal specimen of H. Ranzii, which had only four, instead of five arms. Count Pourtales recognised among the corals several similar to those which he had obtained by dredging in or near the Gulf Stream, and described in the latest No. (4) of the "Illustrated Catalogue of the Museum of Comparative Zoology at Harvard College," the presence of which on the coast of Barbados serves to indicate the close similarity of submarine life in those two distant localities.
The next two days, or rather the night of the next, and the greater part of the following day, were spent in dredging in the neighbourhood, in a depth of 60 to 120 fathoms, about a mile from the shore, whence Mr. RAWSON has procured his fine specimens of Pentacrinus Mülleri. The Holopus was found on the opposite side of the island. The results were beyond the expectations, or even the hopes, of the most sanguine of the party. Only dead fragments of the Pentacrinus were obtained, but among the abundant spoils were four specimens of a new genus of Crinoid, without arms on the stem, (like Rhizocrinus?) which remained alive, with the arms in motion, until noon on the following day, under the excited observation of the party. A number of deepsea corals, alive, crustacea, sea urchins of new species, star fish, sponges (crutaceous, jurassic,) and corallines, &c., and a rich harvest of shells, were obtained. Among these was a splendid live specimen of Pleurotomaria Quoyana, F and B, of which genus Chenu writes that only one living species, and of that only one specimen, is known. The animal exhibited remarkable affinities,