Pomona College, Claremont, California 3 



A very large and finely preserved female, recently sent me by 

 Prof. William A. Hilton, now settles the matter without question. 

 This specimen (S. S. B. 453) was obtained from near Avalon, 

 Santa Catalina Island, California, in the summer of 1915, by 

 Mr. W. F. Hamilton. Unfortunately I have no comparative 

 material from other regions available, so that with only the aid of 

 such figures and printed descriptions as are at hand, the specimen 

 cannot be distinguished from the Mediterranean 0. tiihcrcidata, de- 

 scribed and named by Rafinesque just over one hundred years ago. 

 As tiiberculata happens to be the only species of the genus enjoy- 

 ing general recognition, and as it is a pelagic creature with the pos- 

 sibility of very wide dissemination, the identification seems never- 

 theless to be reasonably certain, though it should be admitted that 

 the areas it Is alleged to inhabit are so widely separated that ade- 

 quate material may later reveal differences which will be thought 

 worthy of recognition. 



In addition to Mediterranean localities the species has been re- 

 ported from Vineyard Sound, Massachusetts, from the West In- 

 dies, and from Japan. 



The sexes in this genus, as in the related Argouaiita and Trem- 

 octopus, show such extreme dimorphism, that the description of one 

 applies in scarcely a single particular to the other. The female 

 Ocythoc, however, is very easily distinguished from other cephalo- 

 pods by the large Octopus-like body, the ventral surface of which Is 

 very curiously ornamented with numerous conspicuous cartilaginous 

 tubercles, connected by radiating ridges. The enormous and power- 

 ful funnel is also noteworthy. 



The more important measurements of the present specimen are 

 appended below, many of them necessarily more or less estimated. 



MEASUREMENTS 



Total length 440 mm. 



Length of body (dorsal) _ 160 mm. 



Length of body (ventral) 155 mm. 



Tip of body to base of dorsal arms._ _ 170 mm. 



Width of body 1 15 nim. 



Width of head 74 mm. 



