A. E. Yerrill — North American Cephalopods. 
197 
Special Descriptions of the Atlantic Coast Species. 
Architenthis Steenstrup. 
Oplysninger om Atlanter, Collossale Bkeksprutter, Forhandlinger Skand. Xaturf., 
1856, vii. p. 182, Christiana, 1857. 
Size large. Body stout, nearly round, swollen in the middle. Caudal 
fin, in the typical species, very small, sagittate (very large, broad, 
rhomboidal in A. megaptera).* Head large, short. Eyes very large, 
oblong-ovate with well-developed lids and anterior sinus. Sessile arms 
stout, their suckers large, very oblique, with the edges of the horny 
rings strongly serrate, especially on the outer margin. The margin 
has around it a free-edged membrane, which closely surrounds the 
denticles when the sucker is used, and allows a vacuum to be produced. 
Tentacular-arms very long and slender, in extension, the proximal 
part of the club furnished with an irregular group of small, smooth- 
rimmed suckers, intermingled with rounded tubercles on each arm, 
the suckers on one arm corresponding with the tubercles of the other, 
so that, by them, the two arms may be firmly attached together 
without injury, and thus used in concert ; other similar suckers and 
tubercles, doubtless for the same use, are distantly scattered along 
the slender part of these arms, one sucker and one tubercle always 
occurring near together. The internal shell (known only in one 
species) is thin and very broad, expanding from the anterior to the 
posterior end, with divergent ribs. 
This genus is closely allied to Ornraastrephes , from which it may be 
best distinguished by the presence of the peculiar suckers and tuber- 
cles for uniting the tentacular-arms together. A small cluster of 
smooth-edged suckers also occurs at their tips. 
Architeuthis Harveyi Terrill. 
J feyaloteuthis Harveyi Kent. Proc. Zool. Foe. London, 1874, p. 178. 
Architeuthis nwnachus Terrill, Amer. Journal Science, vol. ix, pp. 124, 177, PI. ii, 
iii. iv, 1875; vol. xii, p. 236, 1876. American Naturalist, vol. ix, pp. 22, 78, 
figs. 1-6, 10, 1875, (? non Steenstrup). 
Ommastrephes harveyi Kent, Proc. Zool. Soc. London, 1874, p. 492. 
Ommastrephes ( Architeuthis ) monachus Trjon, Manual of Conchologv, I, p. 1S4, PI. 
83, fig. 379, PI. 84, figs. 380-385, 1879. (Descriptions compiled and figures copied 
from the papers by A. E. T.) 
Plates XIII, XIV, XV, XVI. XVIa. 
The diagnostic characters of this species, so far as determined, are 
as follows; Sessile arms unequal in size, nearly equal in length, 
* This species differs so much in dentition and other characters from the typical 
forms, as to deserve separation, as a subgenus, or perhaps as a distinct genus, which I 
propose to call Sthenoteuthis. 
