SOME NEW AND RARE CEPHALOPODA. 119 



muscles have the smallest development, and the mantle-nerves which perforate them 

 are, prior to the formation of the ganglion, relatively the shortest that are met with in 

 the Dibranchiate order. 



I carefully examined the ova of Mr. Bennett's small specimen, but obtained no re- 

 sults bearing upon the interesting question before alluded to, the development of the 

 embryo not having proceeded to the degree necessary for the appearance of the shell, 

 supposing it to be formed in ovo. The observations I'ecorded in the 'Philosophical 

 Transactions,' by Mr. Bauer (1817), and in the ' Zoological Journal/ by Mr. Broderip, 

 (vol. iv. p. 57.) are, for the same reason, inconclusive as to this point. 



The ova of the Argonauta Mans were nearly of the same size as those of the Arg. 

 Argo at a similar stage of development, viz. -^Vth inch in length, and ^^th in diameter ; 

 but they are of a more regular oval form, not tapering to the end opposite the attach- 

 ment of the peduncle. Examined with transmitted light, they are composed of an ex- 

 terior, smooth, colourless, transparent, tough, elastic, cortical tunic ; next of a more 

 delicate membrane (the chorion), containing a straw-coloured transparent albuminous 

 fluid : in this fluid there was an irregular mass of semi-opake granules, in which was im- 

 bedded an opake dark vitelline body, surrounded by a membrane and pellucid fluid. 

 The form and proportion of the opake vitelline body and its transparent investing mem- 

 brane varied in size and shape in different ova : I have carefully figured one of the most 

 remarkable in this respect (fig. 15), in which for a moment I entertained the exhilarating 

 idea, that the nucleus of the real shell was contained within it : on tearing open the ex- 

 ternal tunic, however, the contained substance turned out to be nothing more than the 

 volk, separated by an intervening stratum of clear fluid from the transparent membrana 

 vitelli, and the whole substance of the opake mass separated into the flakes, granules, 

 and globules of oil, of which the vitellus is usually composed : there was not a trace of 

 any consistent parts of an embryo, nor the slightest particle of calcareous matter. 



The mutilated Decapodous Cephalopod, obtained at Port Jackson, New South Wales, 

 and transmitted to me by Mr. Bennett, consisted only of the head and principal viscera, 

 and was consequently too imperfect to allow of its being satisfactorily determined, even 

 as to its genus. But as the suckers were arranged in a double alternate row on each of 

 the short arms, it was evidently not a Sepia of Cuvier, while the denticulated margins 

 of the horny rims of the suckers show that it may have belonged either to the genus 

 Sepioteuthis, Fer., or Loligo, Cuv. As in some species, both of Sepioteuthis and Loligo, 

 the outer lip gave off" eight short processes, on the inner surface of which, near their ex- 

 tremity, were three or four smaU suckers, attached by peduncles, and having precisely 

 the same structure as those of the eight large exterior arms. In this repetition of the 

 ordinary series of cephalic prehensile processes, we may perceive an evident analogy to 

 the internal series of processes (labial tentacles) which exist in the Nautilus. In some 

 species of Calamary, indeed, as in the Loligo Pealii, Le Sueur, the acetabuliferous labial 



