Antarctic Expedition . 237 
cepting 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 beino* 
intermixed or lost, as they are very likely to fall olf 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 examined 
even before they leave the egg, by opening the egg under a 
single microscope. Drawings of these changes are very de¬ 
sirable, and when practicable the eggs and young ones in 
different stages should be preserved in spirit in snort glass 
tubes. The smaller oceanic Crustacea offer a prolific and 
hitherto unexplored field of investigation. 
Among the floating Mollusca likely to be met with in the 
tropical latitudes is the Spirula 9 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 be watched in a vessel of sea water, with 
reference more especially to the pow r er 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 
water, in order to determine if it contain a gas; the nature of 
this gas should likewise, if possible, be ascertained. As a part 
of the shell of the Spirula projects externally at the posterior 
part of the animal, this part should be laid open in the living 
Spirula , in order to ascertain how T 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 cap¬ 
tured, the same observations and experiments should be made 
on that species, in which they would be attended with more 
precision and facility, as the species is much larger than the 
Spirula 9 and its shell external. The towing-net should be kept 
overboard at all practicable periods, and drawn up and ex¬ 
amined at stated intervals, as some of the rarest marine animals 
have been taken by thus sweeping the surface of the sea. 
A sketch or drawing of Molluscous and Radiate animals, of 
which the form and colour are liable to be materially altered by 
death, or when put in spirit, will aid materially in rendering 
the description of the species useful and intelligible. The 
Echinodermata and Asterias echinus , and similar forms, should 
be soaked in fresh water previously to their being put into 
spirit. 
Care must be taken not to crow'd too many soft-bodied 
Invertehrata in the same bottle, and to change the spirit or 
preserving liquor at least once, if not oftener. 
2. Fisiies. 
The mode and speed of swimming, living colour, tempera- 
