regular curve; beaks small, submedially located, distinct but inconspicuous; umbonal ridge slightly developed, curved, passing near the dorsal and posterior borders. Surface marked by the usual concentric lines of growth.

Length, 20 millimeters; height, from base to beaks, 18 millimeters. (Museum No. 8362.)

This species is readily recognizable by its comparatively narrow pos terior side, its deeply convex basal border, and slight convexity of the valves.

Position and locality.-Cretaceous strata, Monument Creek, Colorado, where it was obtained by Dr. A. C. Peale.

GASTEROPODA.

Genus PLANORBIS Guettard.

PLANORBIS ÆQUALIS (sp. nov.).

Shell rather small, coiled nearly in a plane, apparently sinistral; whorls apparently 4 or 5, in close contact but only slightly involute, broadly convex upon the periphery, but their sides more narrowly convex, their transverse diameter greater than that which corresponds with the plane of the coil.

Surface marked by a considerable number of revolving raised lines or slight angulations, which are crossed by the usual lines of growth. Diameter of the full coil of the largest example discovered, 6 millimeters. (Museum No. 8909.)

This is apparently the only species of typical biumbilicate Planorbis that has yet been discovered among the fossil fresh-water fauna of the Western region, and it therefore needs no detailed comparison.

Position and locality.-Green River Group, Eocene, Henry's Fork of Green River, Southern Wyoming.

Subgenus GYRAULUS Agassiz.

PLANORBIS (GYRAULUS) MILITARIS (sp. nov.).

Shell very small, dextral, depressed-convex above, umbilicate below; volutions two and a half to three and a half, convex on all sides except the inner, which is very narrowly flattened against each preceding coil; suture deeply impressed both above and below; surface marked by comparatively coarse lines of growth.

Diameter of the full coil of the larger examples in the collection, 4 millimeters. (Museum No. 8594.)

This form was noticed but not named by me in vol. iv, U. S. Expl. & Sur. West of the 100th Merid., p. 210. At that time I was not satisfied as to the mature condition of these shells, but by careful examina

tion of a larger number of examples there seems to be no reason for doubt upon that point.

The subgenus Gyrautus has not heretofore been published as occurring among our large fossil pulmonate molluscan fauna of the West, but at least two other species probably exist there, one in the Bear River (Laramie) strata, and the other in those of the Green River Group.

Position and locality.-Head of Soldiers' Fork, Utah, where they were obtained by one of the parties of the survey in charge of Lieutenant Wheeler. The true age of the strata is not at present definitely known, but it is understood to be either that of the upper portion of the Laramie or the lower portion of the Wahsatch Group.

Genus LIMNEA Lamarck.

Subgenus LEPTOLIMNEA Swainson.

LIMNEA (LEPTOLIMNEA) MINUSCULA (sp. nov.).

Shell rather small, moderately attenuate; spire much longer than the aperture; volutions six or seven, moderately convex, the distal border very narrowly appressed against each preceding coil; aperture small, elongate, subovate; columellar fold distinct, but not large. Surface marked by distinct lines of growth, but no revolving lines have been detected.

The only two examples of this species that have been discovered are broken, but the full length of the larger one is estimated at 9 millimeters; diameter of last volution, 3 millimeters; length of aperture, 3 millimeters. (Museum No. 8907.)

Position and locality.-From strata belonging to either the basal portion of the Green River Group or the upper portion of the Wahsatch Group, about three miles east of Table Rock Railroad station, Southern Wyoming, where it is associated with Planorbis cirratus White, and also a small Limnæid that is probably referable to Acella Haldeman.

Genus HELIX Linnæus.

Subgenus PATULA Haldeman.

HELIX (PATULA) SEPULTA (sp. nov.).

Shell convex above; umbilicus moderately wide; volutions about six, convex upon all sides except the inner; suture impressed; surface regularly but minutely ribbed, the ribs having the same direction as the lines of growth.

All the examples discovered are distorted by pressure, but the diameter of the full coil of the largest example was about 12 millimeters and its full height about 7 millimeters. (Museum No. 8908.)

Position and locality.-The coal-bearing series of strata at Evanston, Wyo., where it is associated with H. evanstonensis White and other forms. These strata belong either to the upper part of the Laramie or the lower portion of the Wahsatch Group.

ARTICULATA.
VERMES.

Genus SPIRORBIS Lamarck.

SPIRORBIS? DICKHAUTI (sp. nov.).

Shell discoid, one side being nearly flat and the other broadly umbilicate; volutions about five, partially embracing but all of them visible, somewhat rugose but increasing in size with considerable regularity; peripheral side of the volutions flattened or gently convex, having a single revolving raised line along its middle and another similar one at each border, where it sharpens the angularity between the lateral and peripheral sides; outer portion of both the lateral sides of the volutions concave, and the inner portion convex, giving the last-named portion a greater transverse diameter than the outer portion, the larger part of which is embraced by the next succeeding volution; aperture small, round, and apparently, but not really, contracted. The cavity being round, the outer portion of the test only partakes of the irregu larity described, and seems to have been deposited as an encrustation. upon the first-formed inner portion, that of adjacent volutions seeming to blend, obscuring the suture. Besides a considerable degree of rugosity, the surface shows under the lens a peculiar granular or rather an etched appearance.

Greatest diameter of the full coil of the largest example discovered, 9 millimeters; greatest diameter of the outer volution, near the aperture, 23 millimeters. (Museum No. 9073.)

In size and general aspect this species resembles S. rotulus Morton sp., from the Cretaceous of New Jersey, but although doubtless congeneric, it differs from that species in the character of its surface ornamentation, and in having a round instead of quadrangular aperture. This shell is referred to the shell-bearing worms and not to the mollusca on account of the peculiar character of the test. It probably does not strictly belong to the genus Spirorbis, but it is regarded as at least a closely related form.

Position and locality.-Cretaceous strata near Little Rock, Ark., where it was obtained by Mr. E. O. Ulrich, and also by Mr. H. E. Dickhaut, in whose honor the specific name is given.

CRUSTACEA.

Genus CALLIANASSA Leach.

CALLIANASSA ULRICHI (sp. nov.).

Hand quadrate, flattened; inner face less convex than the outer; both upper and lower edges acute, the lower one more so than the upper, and finely crenulate; fixed finger slender, plain, its transverse section subAug. 24, 1880.

Proc. Nat. Mus. 80-11

triangular, gently curved, shorter than the hand; movable finger larger and stronger than the fixed one, having a moderately strong prominent ridge upon the inner side, between the front end of which and the extremity of the finger there is sometimes a distinct tooth. Surface nearly smooth, but some examples are granulate about the middle of both sides of the hand, and several small foramina are observable along the upper margin of the movable finger.

Length of hand, 13 millimeters; breadth, 10 millimeters; thickness, 4 millimeters. (Museum No. 8910.)

Position and locality.-This species has been sent to the United States National Museum by Mr. E. O. Ulrich, in whose honor the specific name is given. He obtained it from Cretaceous strata near Little Rock, Ark. Associated with it, besides certain characteristic Cretaceous mollusca, there are several separate movable fingers which plainly belong to another decapod crustacean; but although complete in themselves, they constitute too small a portion of the animal to satisfactorily base a specific description upon them.

A CATALogue of THE BIRDS OF NORTH AMERICA.

By ROBERT RIDGWAY.

INTRODUCTION.

During the interval of twenty-one years which has elapsed since the publication of the last Smithsonian catalogue,* a great advance has naturally been made in our knowledge of North American ornithology; and so numerous and important are the changes which have resulted, through additions of new species, rectifications of synonymy, etc., that a new list seems desirable to take the place of the old one.

The total apparent number of species given in the old catalogue has been increased only from 738 to 764, a slight numerical discrepancy which it is necessary to explain. From the catalogue of 1859 there have been eliminated no less than 62 names, which are either not entitled to a place in the North American fauna or which have been degraded to varietal or sub-specific rank, the number of the species in the latter case being here simply duplicated as many times as there are varieties of a species. To offset this large reduction, 59 valid new species have been described since 1859, and 77 added, or restored, to the fauna, the acces sions thus numbering 127 species, or 65 more than the eliminations. The forms considered to be of merely subspecific rank number 160, which, added to the 764 valid species recognized, gives a total of 924 definable forms composing the North American avian fauna, as now understood.t It is found impracticable to here distinguish, in all cases, between

*Two catalogues of North American birds have been issued by the Smithsonian Institution, as follows:

(1) Catalogue of North American Birds, chiefly in the Museum of the Smithsonian Institution. By Spencer F. Baird, Assistant Secretary of the Smithsonian Institution. Washington: Smithsonian Institution. October, 1858. 4to, paper. 1 p. 1., pp. xviilvi. [Reissue, with new title-page, of pp. xvii-lvi of Vol. IX, Pacific R. R. Reports ("Birds of North America"). Includes, besides the list of 738 species, with habitats, tables of the higher groups, and lists of extralimital species (23 in number) treated in the general report, and of others (31) claimed, on apparently insufficient grounds, as North American; also a summary of the number of species given in the works of Wilson, Bonaparte, and Audubon.]

(2) Catalogue of North American Birds, chiefly in the Museum of the Smithsonian Institution. By Spencer F. Baird. First octavo edition. Washington: Smithsonian Institution. [Smithsonian Miscellaneous Collections, No. 108. ] 1859. 8vo. 2 p. ll., pp. 19+2. [Essentially the same as the quarto list, but without habitats, and the matter relating to classification, etc. The two additional pages are an alphabetical index of the North American genera. As in the quarto list, there are, ostensibly, 738 species, but 22 numbers are duplicated, making a total of 760 names in the list.]

TA full analysis of the changes made in this catalogue is given on pages 213-234.