218 
.4. E. Yerrill — North American Cephalopoda. 
the harder portions have decreased from 5 to 10 per cent, from the 
measurements taken when first received by me.* When first received 
in 1875, the upper mandible measured lll mm in total breadth (front 
to back) ; 88 mm from tip of beak to anterior end of palatine lamina ; 
20 mm from tip of beak to the bottom of the notch. The lower man- 
dible measured 96 mm in total length ; 80 m,n from tip of beak to inner 
end of alae ; 19 mm from tip to bottom of notch. 
At the present time (Jan., 1880), the breadth of the upper mandible 
is about 90 ,nni ; from tip of beak to anterior end of palatine lamina (at 
junction with anterior edge of alae) 89' nm ; tip of beak to bottom of 
notch, 19 ,J,ra ; breadth of palatine lamina, 58 mm ; beak to posterior end 
of frontal lamina, 90 mm ; beak to posterior lateral edge of alae, 43 ,nm ; 
notch to end of anterior edge of alae, 33 mm ; notch to end of hardened 
or black portion of same (proper cutting edge), if 1111 "; transverse 
breadth at notches, 16 rnm . The lower mandible measures, in length, 
82 m "‘ ; beak to inner end of alae, 67 ; to bottom of notch, 18 ; breadth, 
alae to mentum, 78; end of alae to outer side of gular lamina, 84; 
inner side of gular to mentum, 50; breadth of gular, 44; breadth of 
alae, anterior to posterior edge, laterally, 29; tip of beak to posterior 
ventral end of mentum, 33 ; tip to posterior lateral border of alae, in 
line with cutting edge of rostrum, 45 mm ; posterior lateral border of 
alae to end of gular, 40; depth of notch, 3; breadth of tooth, 8; 
notch to end of cutting or hardened edge of alae, 20; to inner end of 
alae, 55; breadth transversely, across teeth, 16 ,um , (see also table of 
measurements of jaws). 
The beak of the upper mandible is sharp, strongly and regularly 
curved, most so near the tip ; a radial ridge runs from the notch to 
the lateral border of the alre ; the anterior or cutting edges of the ala? 
are somewhat convex and irregularly crenulate. The lower mandible 
has a sharp beak, with a slight notch close to the tip ; the cutting 
edges of the rostrum are otherwise nearly straight; the notches at the 
base are deep and narrow V-shaped. The teeth are rather prominent, 
obtuse, slightly bilobed at the summit ; the one on the right side of 
the mandible is more prominent than the other, owing to the fact 
that the edge of the ala, beyond it, is more concave in outline. There 
is also a broad and slightly prominent lobe in the middle of the 
* There is no reason to suppose that the shrinkage has been any more in this case 
than in the others, but I have not had an opportunity for making comparative meas- 
urements from the same specimens when recently preserved, and again after long pre- 
servation in alcohol, except in one other instance (Xo. 5), in which a similar shrinkage 
was evident. 
