for the British Antarctic Expedition. 73 



unless the soft mass, which tills a large portion of the body, 

 consisting of the li^'er, &c. be removed. Each specimen of 

 this class, excepting the very minute ones, which will be best 

 preserved in small phials or glass tubes, should be wrapt in a 

 piece of very soft, thin linen or cotton cloth, to prevent the 

 legs from being intermixed or lost, as they are very likely to 

 fall oiF after having been a short time in spirit. 



A very important object of investigation is the development 

 of the Crustacea, from the earliest period at which they can 

 be observed to the perfect state. They may be readily exa- 

 mined before they leave the e%'g, by opening the &^'g under a 

 single microscope. Drawings of these changes are very de- 

 sirable, and when practicable the eggs and young ones in dif- 

 ferent stages should be preserved in spirit in short glass 

 tubes. The smaller oceanic Crustacea otFer a prolific and 

 hitherto unexplored field of investigation. 



Among the floating Mollusca likely to be met with in the 

 tropical latitudes is the Spu'ula, a small Cephalopod with a 

 chambered shell. An entire specimen of this rare mollusk is 

 a great desideratum ; and if it should be captured alive, its 

 movements should bo watched in a vessel of sea-water, with 

 reference more especially to the power of rising and sinking 

 at will, and the position of the shell during those actions. 

 The chambered part of the shell should be opened under wa- 

 ter, in order to determine if it contain a gas ; the natm-e of 

 this gas should likewise, if possible, be ascertained. As a 

 ])art of the shell of the Spirula projects externally at the pos- 

 terior part of the animal, this part should be laid open in the 

 living (Spirula, in order to ascertain how far such mutilation 

 would affect its power of rising or sinking in the water. In 

 the event of a living pearly Nautilus (Nautilus Pompilius) 

 being captured, the same observations and experiments should 

 be made on that species, in which they Avould be attended 

 witli more precision and facility, as the species is much larger 

 than the Spirula, and its shell external. The towing net 

 should Ijc Icept overboard at all practicable periods, and drawn 

 up and examined at stated intervals, as some tjf the rarest ma- 

 rine animals have Ijeen taken by thus sweeping the surface of 

 the sea. 



