SOUTH AFRICAN CRUSTACEA. 
PARE: TE 
BY THE 
Rev. THOMAS R. R. STEBBING, 
MAX, BaksSey, SHGs Tose (hoe.S. 
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In the present contribution two new genera are instituted. 
One of them, Exodronidia, based on Studer’s Dromidia spinosa. 
appeals for attention by the fact that the hitherto undescribed 
male proves to be furnished with rudimentary appendages 
on four segments of the pleon. The other, Leontocaris, is 
remarkable among the Hippolytidae for the very unsym- 
metrical constitution of the second trunk-legs, making them 
according to the old classical idiom a pair that is not a pair. 
A species here added to the Dromidean genus Dynomene 
will be found to have peculiarities not unworthy of notice. 
The new prawns, Penaeus caeruleus and Sergestes glortosus, 
are not in general structure exceptional members of their 
respective genera. The Penaeus, however, has one very 
unusual character. In the ordinary preservative media 
which tend to bleach most crustaceans this species, at any 
rate for many months, retains unchanged the fascinating 
tints of blue with which it is adorned when living. The 
Sergestes for its part appears to surpass all congeneric rivals 
in the abundance of its luminous organs. Several species 
are discussed which do not claim to be new. The object 
has been in these cases either to throw some new light on 
the organisation of the species themselves, or to enable those 
engaged in the modern studies of variation and zoothalasso- 
graphy to test the accuracy of the identifications offered. 
It should be borne in mind that when all the available figures 
and descriptions relating to a particular genus have been 
compared, it is still often far from easy to determine whether 
a specimen in hand can or cannot be referred to any of them. 
Characters perhaps have been detected which in the abstract 
would entitle it to rank as a distinct species. But the decision 
may be rendered uncertain by various considerations. Some 
of the. earlier descriptions may be manifestly imperfect, of 
B 640. B 
