046 GEOFFREY SMITH. 
from which either of the two divisions might be derived. We 
also saw that the Anaspidacea, in their external characters, 
approached nearer to the Decapoda, than to the Huphausiid 
type of the Eucarida, and this, again, appears to be the case 
in the internal anatomy. ‘This would indicate that the 
Euphansiacea are a late offshoot from the Decapodan stock, 
and if this conclusion is accepted it is evident that the old 
group of the Schizopoda, including the Mysidacea, Huphau- 
siacea and Anaspidacea is an unnatural assemblage and must 
be abandoned (see phylogenetic tree on p. 551). 
4. Bronomics: (Hasrrs, Repropuction AND DistTrrBuTION). 
(a4) Habitat and General Habits. 
Anaspides tasmaniz inhabits deep pools of rivers or 
tarns on the mountains of southern and western ‘l'asmania ; 
the water in which it lives is always absolutely clear and 
cold, and the animal clambers about upon the stones or 
among the submerged mosses and liverworts at the bottom 
of the pools. It very rarely swims, though it occasionally 
does so in a lazy fashion, and it will occasionally rise to the 
surface of the water and turn over on to its back in the 
manner of a Phyllopod. Its usual mode of progression is 
walking or running in the attitude presented in Pl. 11, fig. 1; 
when alarmed it darts forwards or sideways by powerful 
strokes of its abdomen and tail-fan. I never observed it to 
spring backwards, a movement of which it appears to be 
incapable. 
The exopodites of the thoracic limbs are not used in 
locomotion to any appreciable extent, their function being 
to keep the water agitated round the gills and so assist in 
respiration. Hyven when the animal itself is stationary the 
exopodites can be seen to be in a continual waving motion. 
As remarked before, the body is always held perfectly flat 
and unflexed whether the animal is walking, swimming, or at 
rest. 
