A TABLE FOR STUDENTS Sic 
According to the table the family can always be as- 
certained by the external characters, except in the case 
of the females of the Vaunthompsoniidz and Leuconide, 
and there the eye is generally available, since it is absent 
from all the Leuconidz, and indistinct only in one genus, 
Leptociima, of the Vaunthompsoniidee. The Campylaspide, 
which in the table are but shghtly distinguished from the 
Nannastacide, are strongly distinguished externally both 
from them and all other Cumacea by the backward bulging 
carapace, as also by the stiliform molar process of the 
mandibles and internally by the single pair of liver 
tubes. 
The genealogical relationships of the Cumacea are ob- 
scure. ‘The second antennz of the male resemble what is 
often seen in the Amphipoda. The epipod of the first 
maxillipeds helps the respiration, as in the Myside and 
cheliferous Isopods, but with the important addition of 
sessile branchial sacs. In the swimming branches on 
some of the pereeopods there is a weighty resemblance to 
the Myside. The mouth-organs make some approaches 
to those of the Isopoda, and, as with them, the young are 
hatched before the development of the last pair of perzeo- 
pods. The pleon recalls the palaeozoic Phyliccarida and 
their existing representative Nebulia. 
It will have been seen by the number of genera and 
species to‘which the name of G. O. Sars is attached that 
he has made a special study of this sub-order, and this 
sketch of it is deeply indebted to his numerous and lumi- 
nous works upon the subject, to which, indeed, must be 
credited the clearness and accuracy with which this small 
but very interesting group is now known. 
