1908.] some other Fresh-water Crustacea from Tasmania, 467 
assist the walking movement, spreading out laterally from the body in the 
position shown in fig. 1 (Plate 13). 
This unflexed posture, besides giving a very unshrimp-like appearance to the 
animal, is important, because the Carboniferous fossils referred to above are 
generally preserved in this condition, showing that they probably followed a 
~gimilar habit of life. 
Anaspides appear to be omnivorous, as they will feed upon the dead bodies 
of insect larve or even upon one another; but their chief food is the algal 
slime covering the rocks among which they live, and they also browse upon 
the shoots of submerged mosses and liverworts. 
There is a point in regard to the function of the exopodites of the thoracic 
limbs which can only be observed in the living animal, and has been missed 
by previous authors; these exopodites are not locomotory in function, but are 
kept in a continual waving motion even when the animal is stationary, and 
serve to keep up a current of fresh water round the gills. Their function 
appears to be entirely respiratory. 
All the numerous specimens. observed appeared to be entirely free from 
any parasites, and the only native fish inhabiting the waters where it occurs 
is the little Mountain Trout (Galaxias truttaceus), which is probably not a 
formidable enemy. The introduced English trout, however, which are multi- 
plying so rapidly in the Tasmanian rivers and lakes will probably end by 
exterminating the shrimp. 
Anatomy.—There is very little to add to the descriptions that have been 
given of the external anatomy and form of the appendages, except in relation 
to the genital openings, which were erroneously described by Thomson. Both 
the male and female openings are in the normal Malacostracan position, 2.e., 
the vasa deferentia open at the bases of the last pair of thoracic legs, and the 
oviducts at the bases of the last pair but two. The large median opening on 
the ventral surface of the last thoracic segment in the female is not, as 
Thomson supposed, the aperture of the oviducts, but opens into a blind 
pouch, the spermatheca, where the male deposits the spermatozoa. This 
spermatheca is unparalleled in other “ Schizopoda,” and seems to point to 
Decapodan affinities. 
The internal anatomy, studied in fresh material and by means of serial 
sections, reveals several points of importance. 
The heart, which is tubular and elongated, stretches through the whole of 
the thorax, and passes without a very definite constriction into the abdomen. 
The ostia, of which there are apparently only a single pair, are situated in a 
constriction in the third thoracic segment. The structure of the heart recalls 
very closely that of the Mysidacea. 
