94 BRITISH ENTOMOSTRACA. 



part, the carapace is marked with a series of circular, flat- 

 looking canals (t. VII, f. 1 a), which resemble very much 

 the canals described on the carapace of the Apus, and 

 which probably serve the same purpose. 



The head is very small, compared with the size of the 

 animal, flattened on the summit, and straight on its front 

 margin, which terminates in a short, projecting beak. 

 On its posterior surface it is marked near the edge with 

 a strong ridge, which appears to commence just above the 

 eye, and runs down to immediately above the heart ; 

 while a similar elevated ridge seems to encircle the root 

 of the antennae. 



The eye is of a moderate size, but smaller in propor- 

 tion than in the pulex. 



The inferior antennaj are small, compared with the size 

 of the animal, the filaments being finely and densely plu- 

 mose, but the antennules are ^vell develoj)ed, compared 

 with the pidex; consisting of a short tubercle, which sends 

 off" several short seta3. 



The sixth segment of the body sends off" five projec- 

 tions ; the two posterior being in the form of long spurs, 

 and curved, the points reaching backwards and upwards, 

 the other three being short and obtuse, all finely serrated. 

 The fifth sends ofi" two filaments, which are much shorter, 

 proportionally, than in the two preceding species, but 

 finely plumose. 



The abdomen is rather long, broad at the upper part, 

 rather deeply sinuated at about half its length, and narrow 

 towards the extremity. It is beset on the under edge 

 with about fifteen teeth, the sinuation being free from 

 them, and is terminated by two long, curved spines. 



The young are very numerous, and I have sometimes 

 counted upwards of thirty born at one accouchement. 

 When the ova are in the ovarium, and even when the 

 young are considerably developed, they present a beautiful, 

 green -colom-ed mass, showing tlu'ough the transparent 

 carapace. 



This is by far the largest species of the family I have 



