26 ZOOLOGICAL COLLECTIONS MADE DURING [Jan. 4, 



The odontophore consists of sixty-two rows of teeth, each row 

 composed of a transverse series of seven. The central tooth is the 

 largest, having a large acutish central prong and a small subbasal 

 one on each side. The next tooth on either side is considerably 

 smaller, with an acute central fang, and a smaller somewhat hooked 

 one on the outside, and none on the inner. The two outer teeth are 

 long, simple, curved and acute, the outermost having a slight sinu- 

 ation in the outer curved edge. 



The colour of the specimen as preserved in spirit is brownish 

 purple, slightly paler on the inner surface of the arms. The minute 

 dotting so general in this order of MoUusca is scarcely observable in 

 the head before me. 



Dimensions. Length of tentacles 4.50 millims., of ventral arms 270. 



Affinities and Differences. At present only a single species has been 

 described from the Patagonian region. This is the Onychoteuthis 

 fusiformis of Gabb^ "said to have been caught oif Cape Horn." 

 This is a very small animal in comparison with that here described, 

 and, judging from the description, is a distinct species, and not the 

 young form of that now described. The formula of the relative 

 length of the arms is different ; and in 0. fusiformis the lowermost 

 or ventral pair of arms are destitute of a marginal membrane, 

 whilst in O. ingens this feature is strongly developed. The cupules 

 are described by Gabb as being "arranged in a double series, 

 without being either in pairs, nor yet alternating;" on the contrary, 

 in the present species they are most regularly alternating. The 

 tentacles have a different proportional length in relation to the 

 club at the end, in the one form (O. fusiformis) being as 3 to 1, 

 in the otiier as 5 to 1. Besides these distinctions, there are pro- 

 bably others, in the number of hooks on the club, the number of 

 the cups at the extremity of it, the presence of tubercula between the 

 cupules of the carpal group, and in the odontophore, all of which are 

 passed over in the description of the Cape-Horn species. 



The well known O. banksii is also a smaller animal, with compressed 

 lower lateral arms. The formula of relative length is different, the 

 number of hooks on the club smaller, and the cupules of the carpal 

 group fewer ; those on the arms, too, differ in form ; and the odon- 

 tophore offers certain distinctions. 



II. Gastropoda. 



a. Marine. 

 Pleurotoma, sp. inc. 



Hab. Wolsey anchorage, 17 fathoms, brought up on the anchor. 



A single dead specimen of a very interesting form. It apparently 

 belongs to the typical group of the genus, with the slit in the middle 

 of the lip. The apex, consisting of one whorl and a half, is large 

 for the size of the shell, and globose. The rest of the whorls have a 

 strong beaded keel round the middle, and a smaller and less distinctly 



1 Proc. Califoruian Acad. Nat. Sci. 1862, p. 171. 



