206 A. E. Terrill- — North American Cephalopoda. 
The odontophore is about 64 mm in total length, with the dentigerous 
portion, where widest, about 1 l mm in width. The teeth are in seven 
rows, with an exterior row of small, unarmed, thin, rhomboidal plates 
on each side, thus conforming to the arrangement in the other 
ten-armed cephalopods. The teeth are deep amber-color to dark 
brown, and not unlike those of Loligo and Ornmaslrephes in form. 
Those of the median row have three fangs, the central one longest ; 
those on the next row, on either side, have two fangs ; while those of 
the two outer lateral rows, on each side, are acute and strongly 
curved ; the outermost longest and simple, the next to the outer 
often having a small denticle on the outer side, near the base. (See 
Plate XV by, figs. 1, 2, 3.) 
The membrane of the odontophore is broad, firm and thick ; the 
dentigerous portion occupies only about a third of its width, in the 
middle or broader portion, where it is bent abruptly back upon itself. 
The lower or ventral portion measures, from the anterior bend to the 
end, 20 mm ; it narrows gradually to the broad obtuse end, the width of 
the dentigerous portion decreasing from 9 to 5 nin , the naked lateral 
membrane decreasing from 8 n '“ to a very narrow border. The 
upper portion, from the bend to the end, measures 42 ,om in length 
(in a straight line). The upper surface is deeply concave and infolded, 
at first, with the lateral membrane broad and recurved ; farther back 
it becomes more flattened, with the dentigerous portion broader (ll ru “ J ), 
while the lateral membrane is abruptly narrowed and then extends 
to the end as a very narrow border. Toward the end the rows of 
teeth become more separated and the teeth smaller and paler, while 
the membrane becomes thinner and narrower. 
The internal shell, or ‘ pen,’ was represented by numerous detached 
pieces, which, after much trouble, I succeeded in locating and match- 
ing, so as to restore both the anterior and posterior ends, and thus to 
gain a fair idea as to what its original structure must have been. 
The texture, form and structure of the pen was somewhat like that of 
Loligo , but it was thinner, and had less definite outlines, and less of 
the peculiar quill-shape seen in the latter. The posterior end, instead 
of being pointed and regular in outline, appears to have been broadly 
rounded, or somewhat truncated, with an indefinite outline, thinning 
out gradually on all sides into a soft fibrous membrane, while the 
shaft, or quill-portion, was. not so distinctly differentiated from the 
broader central portion, but increased in width quite regularly, from 
near the anterior end. The fragments in my possession belong to 
four more or less separated sections. The first section includes eleven 
