546 U. Ss. P. R. R. EXP. AND SURVEYS—ZOOLOGY—GENERAL REPORT. 
In the alcoholic specimen the body is elongated and cylindrical; the fur short, close, and 
compact ; the muzzle very blunt and rounded; the eyes very small, rather nearer the muzzle 
than the ear; the upper lip emarginate, but scarcely fissured or even furrowed beyond the 
emargination. The ears are very small, not as long as the adiacent fur; the concha slightly 
inflexed above; the two roots of the margin separated by a plane interval. The antitragus 
moderate, appearing scarcely sufficient to close the meatus ; the surfaces of the ear apparently 
naked, with only a small fringe of long hairs on the concavity, near the superior margin. The 
legs are very short and weak. The fore feet very large, compared with the hinder, or rather 
longer than from heel to base of toes. Fore claws longest; thumb with a distinct, though 
short and obtuse-pointed claw ; palms with five tubercles. Soles with only five tubercles ; one 
at the bases of the third and fourth toes ; one each at the bases of the second and fifth, and a 
fifth near the inner edge of the sole, as far behind that of the first toe as this is from the tubercle 
of the fifth ; its anterior edge is about midway between the heel and the end of the balls of 
the toes. These tubercles are all large and conical, or pyramidal, and nearly of equal size. 
There is no trace of the sixth, usually seen near the exterior of the sole. The sole is hairy 
as far as the anterior edge of the posterior tubercle, though the hairs do not come up very close 
around it. The tail is very short, scarcely twice as long as the hind feet, which reach as far as 
its middle; it is well covered with hairs. 
In a suckling female but two pairs of teats (inguinal) could be detected. 
The skull of this species (1933) is very short and broad ; the proportions of breadth to length 
being .60 to .97 of an inch, or as 64 to 100. The upper surface is considerably convex in every 
direction. The muzzle is short, the projection anterior to the base of the zygoma being .24, or 
about one-fourth the total length. The nasal bones are subtruncate behind, and extend back a 
little beyond the anterior of the external outline of the zygomatic arch ; the nasal branches of 
the intermaxillary pass about a twentieth of an inch beyond or into the interorbital region. 
The interorbital portion of the forehead is rather broad, as wide as the widest part of the 
muzzle; about .19 the axial length. The cranium narrows suddenly to form the posterior 
portion of the orbit proper, the outline passing directly to the narrowest part of the interorbita] 
portion perpendicular to the axis of the head, which is intersected a very little anterior to it 
middle points. The distance between the vertices of the angles of the cranium is .35 of an inch, 
or rather more than half the diameter of the head. The interparietal bone is subtriangular, 
obtuse angled anteriorly, slightly and irregularly convex posteriorly ; the lateral extremities 
acute angled, sometimes blunt or rounded, scarcely truncate, nor with a projecting point from 
a posterior corner, as in A. riparia. The occipital foremen is nearly round, a little wider than 
high. 
The lower jaw is short and stout, the coronoid process long and curved, rising a little higher 
than the condyle; the condyloid process rather deep. 
The incisors are rather narrow. The upper are deeper antero-posteriorly than wide; their 
anterior surfaces nearly plane or rounding off very slightly ; the width of the cutting edge 
about equal to the length of the anterior upper molar (.09 inch.) The distance from the pos- 
terior base of the incisors to the anterior extremity of the molars is one-third that of the occi- 
put. The line of the molars is one-fourth the length of the skull (.24 of an inch.) The bony 
palate posteriorly has a fossa on either side against the inside of the posterior molar. 
The anterior molar is composed of one anterior, two exterior, and two interior closed tri- 
angles; the first or anterior lateral triangle is interior, the last exterior. The second molar 
