JAN. — MAR. 1857.] votjage from Etigland io 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 iToth sides and carinated on the back 
and below, with a membranaceous lamellar keel," and he adds that 
it has externally much tl^e appearance of a very diminutive umbili- 
cated Nautilus. The Limacina however is a true Pteropod which 
this animal is not, it likewise differs from Limaci7ia, 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 
