Relations of Bunops in the Family Macrotliricidce. 341 
ponding structure of the Lynceidce. In Bunops and Ophryoxus , 
the gill sac is small and rounded. The resemblance to the other 
genera is not particularly close. Macrothrix comes as near to it 
as any other genus, llyocryptus , whose legs are quite different 
from those of the other Maerothricidce , is furthest removed from 
Bunops. Bosmina shows no special relation to Bunops in this 
or any other appendage. 
It would be wearisome and unprofitable to compare all the 
appendages in regard to number and character of hairs and 
spines, and no attempt is made to carry out such a minute com¬ 
parison, the general resemblences only being noted. 
The second pair of legs is much alike in all the Maerothricidce. 
The chief difference, other than those of proportion, etc., concerns 
the development of the inner branch and the structure of the 
peculiar comb like the spines of the distal setae. 
The outer branch of the.second leg of Bunops seems slightly 
developed in comparison with that of the other genera. In the 
Maerothricidce , the outer branch is very small in comparison 
with the Daphnidce , and Bunops seems “to be one of the ex¬ 
treme types of the family in this respect. The comb-like struc¬ 
ture of the setae, possessed by Bunops , is shared by all other 
members of the family except llyocryptus. Of the other genera 
Acantholeberis is least specialized in this regard. 
In the third and fourth legs, there is a great difference in 
the development of the outer branch. This is enormously ex¬ 
panded in llyocryptus , Acantholeberis and Ophryoxus , and much 
less so in the remaining genera. In Bunops , these parts are 
rather less developed than is the case in Macrothrix. It would 
seem as. if the infolding of the ventral edge'of the carapace re¬ 
duced the space and caused a smaller expansion of the legs. In 
number and arrangement of setae of the inner branch, Bunops 
agrees most closely with Acantholeberis , although possessing 
minor peculiarities of its own. 
The fifth leg shows no special resemblance to that of any 
other genus. 
When we come to the results of this comparison, it appears 
that Bunops approaches no one of the other genera of Macro- 
thricidce closely enough to be regarded as a very near ally. In 
