346 ASELLID&. 
is about half a line long, and transparent under the 
microscope. 
‘«« The young in one instance were observed to be hatched 
during the week previous to the 22nd July, but in one 
year each of these specimens had a cluster of white ova 
on the thorax in the middle of September. 
‘‘ The posterior extremity of the young is proportion- 
ably more obtuse than in the parent. Further, unless it 
be immediately or speedily consequent on production from 
the ova, they do not seem to undergo any conspicuous 
metamorphosis. 
*« |xuviation is less frequent here than in many other 
crustaceans. The integument, however, separates in 
two portions, which are nearly white. 
‘‘ This is an extremely pacific, tranquil creature, always 
seeking shelter. Specimens have survived many months 
when kept in confinement.” 
The development of the eggs and young of this species 
has been carefully investigated by De Geer, in his great 
work on Insects, and more recently, in greater detail, by 
Rathke,* from whose elaborate series of illustrations the 
accompanying figures have been selected. 
The eggs having been discharged from the oviduct, 
are entirely destitute of any trace of germ, and are 
retained and hidden beneath the four pairs of large, 
slender, and semi-transparent scales attached to the under 
surface of the body of the female, where the young are 
disclosed, and remain until they have assumed a form 
similar to that of their parents. Our first figure repre- 
sents the egg in its early state, filled with the yolk and 
enclosed in a thin chorion. 
* Abhandlungen zur bildungs und entwickelungs Geschichte des menschen 
und der Thiere. Liepzig, 1832, 4to, Erster Theil, p.3 tab. 1. Translated in 
Annales Sci. Nat., 2 sér. Zool. tom. 2 
ae 
