182 A. E. Verriil—Cephalopods of the North Atlantic. 
the notch at its base is rounded and deep and strongly ex- 
cavated at bottom ; the tooth is broad, stout, obtusely rounded 
at summit, sloping abruptly on the side of the notch, and 
¥ 
it makes, with the cutting edge, an angle of about 1 
inner surfaces of the two sides of the internal plate of the 
rostrum form an angle of about 46°. 
The lower jaw of No. 1 (plate v, fig. 16) is represented only 
by its anterior part, the ale and gular lamine having been cut 
away by the person who removed it. It agrees very well in 
form and color with the corresponding parts of the one just de- 
scribed, but is somewhat smaller. the lateral ridges of the 
rostrum are rather more prominent, and the area within it 18 
narrower and more deeply excavated, especially at the base of 
the notch, where the excavation goes considerably lower than 
the inner margin. The notch is narrower and not so much 
rounded at its bottom. The tooth is about the same in size as 
that of No. 10, and appears to be even more prominent, be 
cause the edge of the als is more concave at its outer base; 
it is also more compressed and less regularly rounded at sut- 
it This jaw measures 1:30 inches from the tip to the pos- 
terior dorsal border of mentum ; -65 from tip to the bottom of 
the notch ; 16 from bottom of notch to tip of the tooth. — 
Both these lower jaws agree in having a very prominent 
tooth on the alar edge, with a large and deeply excavated 
notch between it and the cutting edge, and in this respect differ 
from the two lower jaws of A. monachus in my possession, for 
ond the tooth, is rounded and strongly obliquely i 
10°. € 
