jan.— mar. 1857.] voyage from England to Madras. 155 



completely enveloped in a strong membranous epidermis which 

 extends considerably beyond the mouth of the shell and is at its 

 outer edge prolonged into a keel, situated as in Fig. 7, but wholly 

 membranous and only extending over half the circumfer- 

 ence of the shell. On the inner whorls the epidermis is 

 marked with spiral dotted lines. The shell is not so flatten- 

 ed in the whorls as Fig. 7, but is, like it, provided with 

 an operculum, otherwise it seems to answer to the description 

 of Sowerby's Limacina which he defines as " a thin fragile, spiral, 

 discoid shell, umbilicated on both sides and carinated on the back 

 and below, with a membranaceous lamellar keel," and he adds that 

 it has externally much the appearance of a very diminutive umbili- 

 cated Nautilus. The Limacina however is a true Pteropod which 

 this animal is not, it likewise differs from Limacina, in the shell 

 being carinated, possessing an operculum, and having the aperture 

 dextraL During the next few days the wind was too high, we got 

 nothing, and our nets were repeatedly torn. 



On the 3rd of May, Lat. 30-34 S. Long. 30-51 W. a species of 

 Loligo or Sleeve fish called by the sailors a flying squid, fell on the 

 deck of the ship. This animal belongs to the Cephalopods the 

 highest class of MOLLUSCA which in their more complicated inter- 

 nal organization, and in the possession of organs of sight and hear- 

 ing, and a distinct brain, approximate to the VERTEBRATA. The 

 fact of this mollusc having alighted on the deck of the vessel, is re- 

 markable and instructive, for it is alleged that the MOLLUSCA 

 not having members sustained by jointed and solid levers, cannot 

 make rapid springs, whereas it is evident that some have the power 

 of leaping or springing a considerable height out of the water* 

 This fact has been observed by Bennet and others. I have repeat- 

 edly noticed other species of Cephalopods that had fallen on the 

 deck of a ship or in the chains and this in calm or moderate 

 weather, so that they could not have been thrown up by the agency 

 of the winds or waves, and I have also been informed by several 

 officers of ships, that they may be often seen to execute a sustain- 

 ed flight, like the flying fish when pursued by its enemies. They 

 are said to accomplish this movement with the head back- 

 ward and the tail or arrow-shaped extremity advanced, which I 



