ECHIDNA COCOSA. B13 
Echidna cocosa sp. n. 
Form similar to that of Echidna nebulosa Ahl. Body moderately com- 
pressed ; vent near the middle of the entire length; tail retaining its depth 
until near the extremity, where it tapers rapidly to the bluntly rounded end. 
Head compressed, much arched above the snout, concave in the outline of 
the interorbital region, measuring about one eighth of the total length, depth 
one sixteenth of the entire length and width close upon two thirds as much. 
Snout higher than wide, strongly arched from the lip to the interorbital 
space, one and one half times as long as the eye. Eye medium, one ninth 
as long as the head, two thirds of the length of the snout. Mouth wide, less 
than one third of the head length, hardly extending backward of the orbit 
one diameter of the eye. Teeth of divers shapes and sizes. The anterior 
eighteen or twenty of the upper jaw are larger, swollen at the base and 
moderately sharp at the apex; about seventeen of them belong to the max- 
illary series and are arranged in two series at the sides of the jaw, but one 
in front, those of the outer series being+smaller and alternating with those 
of the inner ; the other two of this group are continuous with the vomerines, 
still larger and depressible, forming a row between the maxillary series. 
Backward of the large teeth there are smaller maxillary teeth in two series, of 
five or six teeth each, which continue farther back in a single series of half 
a dozen teeth. Anteriorly for the greater part of the length in the vomer- 
ine series the teeth are crowded together as if in one to three irregular 
series, not distinct as in 7. nebulosa, but farther back they form a single row 
which reaches farther backward than the cleft of the mouth. On the lower 
jaws in the group at the symphysis there are twelve large teeth or more, of 
which the median two pairs are larger and resemble canines, behind 
the large ones; at the sides the teeth are smaller and form single series. 
Anterior nostril with a short tube; posterior pore-like, above the front edge 
of the orbit. Gill opening smaller than the eye. Vertebra 57 + 66, 
Dorsal rays 186 + 170 ca.; dorsal origin nearly one fourth of the length of 
the head forward of the gill openings. 
In a measure the coloration resembles that of /. nebulosa; there are 
about twenty-eight more or less indefinite and irregular transverse bands of 
brown separated by narrow spaces of lighter, bands and spaces much broken, 
blotched, and varied by lighter or darker. 
