in the Cephalopoda, 95 



The genus Ommatostrephes, D'Orb._, formed of those species of 

 the older genus Lolif/o, in which the eyes are uncovered by the 

 general integument, and the structure differs in many other re- 

 spects from that of the species oiLoligo in the narrower sense ; the 

 genus OnychoteuthiSj Lichtst., with its subgenus Gonatus, Gray ; 

 and the genus Loligopsis as it was pecuharly understood by Ferus- 

 sac and D^Orbigny, which does not appear to stand in connexion 

 with the Cephalopoda upon which Lamarck originally founded 

 his genus Loligopsis, — do not present the same differences in the 

 structure of a single pair of arms in the male individuals. Never- 

 theless, important external differences between the males and 

 females are not wanting, as appears even from Verany's descrip- 

 tion and figure of the two sexes of 0mm. sagittatus, Lamk., and 

 as I can confirm from the examination of both sexes from the 

 Mediterranean. It is, however, not only the comparatively 

 much shorter body and the much longer and stronger arms 

 which distinguish the males from the females, but there is also 

 the remarkable difference, which Verany has overlooked, that in 

 the male both the lateral arms bear suckers several times larger 

 than those of the ventral and dorsal arms, whilst in the females 

 the suckers of the lateral arms do not greatly exceed these in 

 size. In these forms, therefore, I by no means doubt the exist- 

 ence of external sexual distinctions, but only that of a less 

 symmetrical development of one of the pairs of arms with refer- 

 ence to reproduction. In connexion with this, however, I must 

 expressly observe, that although I have had the opportunity of 

 seeing a considerable number of species, — and namely no less 

 than six* of the so-called " Loligopsides," which as a group I 



Under the supposition that this observation is correct (?), it remains a 

 question whether these males do not exhibit the dorsal pair, in the first 

 place, with smaller suckers than the other three pairs of arms, and in the 

 second, analogous to the arms in the above-mentioned three species. It 

 requires a closer investigation to determine whether the two Rossice from 

 the Irish coast, described by Ball, R. Owenii and R. Jacobii, of which the 

 latter is referred to R. macrosoma by Forbes and Ilanley, are not in the 

 relation to each other of males and females of the same species ; at least 

 the former agrees, in the characters of the suckers, with my males, and the 

 latter with my females. See the figures of these two species in Forbes and 

 Hanley, plates N. N. N. and S. S. S. 



* As this group still contains so few species in the system, and as these 

 Cuttle-fishes are very rare in general in museums, it will hardly be super- 

 fluous to refer to this number. The six species above mentioned are all 

 Atlantic ; two of them are very small species of the genus Chiroteuthis, 

 D'Orbigny, with much resemblance to the Lol. zygcena, Ver., described in 

 Verany's work, and figured on pi. 40, and to Lol. vermicularis, Riipp. ; 

 two others are also small species, but belong to the genus Leachia, Les., 

 one of which is the Cranchia (Owenia) megalops, described by Prosch in 

 the Memoirs of this Society ; and a second remarkable species, to which I 

 have given the name of L. Reinhardtii, and which is distinguished from all 



