REPORT ON THE CEPHALOPODA. 



147 



Eight. 



Left. 



30 mm. 



25 mm 



36 „ 



30 „ 



36 „ 



31 „ 



30 „ 



32 „ 



52 „ 



67 „ 



Length of first arm, 

 Length of second arm, 

 Length of third arm, 

 Length of fourth arm. 

 Length of tentacle. 



This interesting species is represented in the collection by only one female specimen, 

 but exhibits such peculiarities as to render it worthy of great attention. 



The form of the body is remarkable for its great dorso-ventral extent, and for the 

 ridge which runs down the ventro-lateral aspect. This is not very prominent, but is 

 similar to the ridge observed in many species of Octopus and Eledone {e.g.. Octopus 

 australis, p. 88 and PI. III. fig. 5, and Eledone cirrosa), but I do not remember to have 

 seen it before in any specimen of Sepia. 



The tentacular club bears the greatest resemblance to that of Sepia elegans, 

 d'Orbigny,^ in respect of its shortness and rounded form, and in the presence of three 

 suckers considerably exceeding the others in size. Sepia tuherculata, Quoy and 

 Gaimard, has also three enlarged suckers, but judging by d'Orbigny's figure,^ these 

 would seem to be along the median line of the club and not nearer to one side 

 than the other as in the present form. It may be remarked, however, that very few, 

 if any, species of Sepia have the club so symmetrical as that figure would indicate, 

 and hence the possibility of inaccuracy in this respect must be borne in mind. This is 

 especially important because, as will be seen immediately, these two species present, in 

 one respect, a close resemblance to each other. 



The shell of the type under consideration is undoubtedly its most remarkable 

 characteristic. In the first place it possesses no trace of a spine, a point in which it 

 resembles Sepia elegans, d'Orbigny, above alluded to, and also the various species of 

 Sepiella, which latter it further resembles in the depth of the siphono-pallial articulation ; 

 in all these, however, the chitinous layer of the shell is covered for the most part by 

 a rough calcareous deposit, and only appears at the margin, and the genus Sepiella is 

 clearly distinguished by its peculiar glandular apparatus. 



The chitinous portion of the shell of Sepia pfefferi is visible over the whole of its 

 dorsal surface, and this fact separates it clearly from all Sepix or related forms, with 

 two exceptions, Septia tuherculata, Lamarck,^ and Hemisepius typicus, Steenstrup.* The 

 former of these has an oval shell, the calcareous portion coming close up to the anterior 

 margin, but narrowing so as to leave large projecting chitinous wings posteriorly, whilst 

 in the form under discussion the chitinous plate is but little larger than the calcareous 

 portion all round. In Hemisepius the chitinous plate is so large as to project far 

 beyond the calcareous centre anteriorly as well as posteriorly. 



1 C^ph. ac^t., Seiches, pi. xxvii. fig. 4. ^ Op. (At, pi. xvii. fig. 13. 



3 Cdph. acit., pi. vi. figs, a, b, c. ^ Hemisepius, Tab. i. figs. 3, 4, 5. 



