276 
A. E. Verrill — North American Cephalopods. 
eter. The under surfaces of the fins, siphon, head, and arms have 
fewer and smaller spots, and are, therefore, lighter colored, and 
appear nearly white when these spots are contracted. 
A fresh specimen, caught in Casco Bay, in 1873, had the following 
proportions: Length of head and body, not including the arms, 
221 mra ; length of caudal fin, 86 ; breadth of fin, 90 ; diameter of body, 
35; length of upper arms, 80; of second pair, 100; of third pair, 
100; of the ventral pair, 90; of tentacular-arms, 182 mm . 
Of our species, I have measured large numbers of specimens, pre- 
served in different ways, and also fresh, and have found no great vari- 
ation in the form and relative length of the caudal fin, among speci- 
mens of similar size and in similar states of preservation, nor do the 
sexes differ in this respect. The young, however, differ very de- 
cidedly from the large specimens in these respects. The modes of 
preservation also cause much of the variation in the proportions of 
fins and arms to the mantle. The two sexes are probably equally 
numerous, but in our collections the females usually predominate, and 
the largest specimens are usually females, though equally large males 
occur. In 31 measured specimens, in alcohol, from various localities 
and of both sexes, the average length, from tip of tail to dorsal 
edge of the mantle, was I76 mm (6-96 inches); from tip of tail to inser- 
tion of fin, 66 mm (2-60 inches) ; average proportion of fin to mantle- 
length, 1:2-68. Among these the proportions varied from as low as 
1 : 2-48, in some of the larger ones (with mantle above 8 inches), up to 
1 : 3*00, in the smaller ones (with the mantle less than 3 inches long). 
The following tables are intended to illustrate the natural varia- 
tion in the proportions, due mainly to age, and the accidental varia- 
tions caused by differences in the modes of preservation and strength 
of the alcohol. 
The specimens from Eastport, Me., designated G. H. I. R., were 
collected at one time, in midsummer, and preserved in the same way, 
in alcohol of moderate strength, repeatedly changed ; at the present 
time the strength of the alcohol is about 80 per cent. They are in 
good condition, moderately firm and not badly contracted. Those 
designated as D. E. F. N. O. P., were also collected at one time, in 
August, and preserved together. They are in fair condition, but not 
so well preserved as the former lot. Those numbered ii to xiv 
were preserved together, about the last of July. They were placed 
in strong alcohol and are hard and badly contracted. J. K. and L. 
were preserved together, but were originally found dead on the beach 
and in a relaxed state. They are only moderately contracted by 
the alcohol. 
