88 
The South Australian Naturalist. 
In this group of the Crustacea there is very often much differ- 
ence in external structure between the sexes so that until this 
fact vras duly appreciated there was much confusion in classihea- 
tion. 
The illustration is that of 
the male of a common spec- 
ies named Zuzara venosa, 
Stebbing, found on our near 
beaches at about half tide. 
This species lives in small 
colonies. Most of them are 
small but amongst them will 
be found larger ones, which 
are adult males and have, as showm in our illustration, a curious 
projection on the back arising from the seventh segment ct 
the thorax, the smaller specimens without this process are females 
or young. It is not knowm why this hard process exists but simi- 
lar ones are found in other species arising from the sixth or 
seventh segment of the thorax or from the anterior division of 
the abdomen. There is an extreme case known in Haswellm 
carnea, Haswmll, in which the process is large and shield shaped 
and covers the wdiole of the abdomen. There are other differ- 
ences among species, one of which is a most extraordinary con- 
dition found in some females with brood, where the mouth limbs 
are degenerate, thus the mandibles have become weakened, lose 
their brown colour, are deformed and incapable of use; the two 
pairs of maxillae also lose their colour and spines, and the 
maxillipeds at their virtal parts are much reduced; their proximal 
parts, however, have been expanded to broad plates and an 
accessory fan produced for the better movement of a current 
of clean water for the use of the developing young as would 
appear. Another very extraordinary condition found in some fe- 
males belonging to different species. As is well known in a large 
number of species of Crustacea, a normal marsupiuvi consisting 
of three part of membranous plates which are outgrowths Irom 
the second, third and fourth pairs of legs, form a receptacle to 
carrv the developing young. In the females in the question the 
full function of the marsupiimr has been suspended and tiie grow- 
ing young are found in pouches or pockets wTich project into the 
body of the mother, these have obscure openings to the exterior, 
but the young apparently first feed on the body of the mother as 
at the end scarcely any of the viscera and onh' a mere shell 
remanis in extreme cases. Another instance of ^‘So careful ofthe 
type she seems. So careless of the single life.’^ 
