300 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [90] 



numerous. The suckers were pure white. The eyes were dark, blue- 

 black, surrounded by an iridescent border. 



The colors change constantly, when living or recently dead, by means 

 of the continual contraction and dilation of the chromatophores. The 

 different tints pass over the surface like blushes. 



In specimens recently preserved in alcohol the same pattern of color- 

 ation is usually visible. The dark dorsal band on the body and head, 

 and the dark patches above the eyes, as well as smaller dark patches 

 in front of the eyes, can be plainly seen. In these darker parts the 

 chromatophores are much crowded, and have a purplish brown color, 

 varying to chocolate-brown in specimens longer preserved. On other 

 parts of the body the chromatophores are more scattered and usually 

 reddish brown in color, with a circular or elliptical outline ; when ex- 

 panded, the larger ones are about l mm in diameter. 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 n,m ; 

 length of caudal fin, 8G mm ; breadth of fin, 90 ram ; diameter of body, 35 IU1 » ; 

 length of upper arms, 80 uim ; of second pair, 100 mm ; of third pair, lOO 1 "" 1 ; 

 of the ventral pair, 90 mm ; 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 varia- 

 tion in the form and relative length of the caudal fin, among specimens 

 of similar size and in similar states of preservation, nor do the sexes 

 differ much in this respect. The young, however, differ very decidedly 

 from the large specimens in these proportions. The modes of preserva- 

 tion also cause much of the variation in the proportions of fins and arms 

 to the mantle. The two sexes are probably equally numerous, but iu 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 17C mm 

 (C.96 inches); from tip of tail to insertion of fin, CG ,lim (2.G0 inches). 

 Average proportion of fin to mantle-length, 1 : 2.08. 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 in the smaller ones (with the 

 mantle less than 3 inches long). 



The following tables are intended to illustrate the natural variations 

 in the proportion, due mainly to age, and the accidental variations 

 caused by differences in the modes of preservation and strength of the 

 alcohol. The effect of strong alcohol is to shrink the fins relatively 

 more in breadth than in length, and to reduce the diameter of the body 

 and arms out of proportion to their length. 



The specimens from Eastport, Me., designated G, H, I, E, were col- 

 lected at one time, in midsummer, and preserved iu the same way, in 



