in the Cephalopoda. 93 



from the Mediterranean, which belongs to the same group as 

 S. Rondeletii, as it has only two rows of acetabula on each arm ; 

 its second and fourth arms also bear large and spherical suckers, 

 and its left dorsal arm is metamorphosed in an exactly analogous 

 manner with that of the preceding, from which, however, it is 

 distinguished by the suckers being larger in proportion at the 

 lower part of this arm, and diminishing more suddenly towards 

 the end of the arm ; they are at the same time rather more 

 pedunculate, and the basal parts of these peduncles are not so 

 strongly amalgamated. The peculiar prehensile part at the root 

 is also less develo])ed. 



In the genus Rossin, so nearly allied to Sepiola, it was to be 

 expected that the behaviour of the arm would be the same. I 

 find that this is actually the case as regards the pair to which 

 the metamorphosed arm belongs, but the metamorphosis itself 

 is very diflFerent. Unfortunately I possess no male of the true 

 European species, but, on the other hand, I have examined five 

 male individuals of the genus Russia from the coast of Green- 

 land. These five individuals decidedly belong to two difi"erent 

 species, but they all agree with each other, and difier from the 

 female individuals, both of the European and Greenland species, 

 which I have been able to examine, in that the three lower pairs 

 of arms, the second, third and fourth pairs, bear considerably 

 larger suckers than the first pair, or the dorsal arms, whilst in 

 the females this pair does not bear perceptibly smaller suckers 

 than the rest; and also that the same first pair, the right and left 

 arms, has the outer row of these suckers, for nearly two-thirds 

 of the length of the arm, standing upon high peduncles, the 

 roots of which are uncommonly strongly developed, compressed, 

 and, in the soft state, almost leaf-like ; between these peculiar 

 peduncles we see folds of skin insert themselves, and other 

 similar folds of skin issue from the roots of the peduncles. (PI. Ill, 

 fig. 1.) These remarkable folds of skin, on closer examination, 

 prove to be only luxuriant developments of the ridges of skin 

 which in the Rossice surround the base or the peduncle of the 

 individual acetabula like cups, as is the case also partially in 

 Sepiola, — cutaneous formations to which sufficient attention has 

 perhaps not been paid hitherto, but which possibly correspond 



est assez sujette a une maladie qui consiste en une durcissement et una 

 croissance beaueoup plus grande des cupules des bras sessiles, qui devien- 

 nent quatre fois aussi gros que les autres, sans que leur cercle come suive 

 la meme proportion. Cette affection allonge les bras, les fait gonfler, ou 

 les rend souvent difformes." Of Sepiola Rondeletii, also, he says, in the 

 explanation of figures, p. 233, and indeed with reference to the very figures 

 (5 & 6j which I have mentioned above as unraistakeably resembling my 

 figure : — " Fig. 5, Individu malade ; ses cupules devenues plus grosses et 

 plus durs. Fig. 6, Portion de bras affecte de la maladie indiquee." 



