422 SPH^ROMID^E. 



joint is obconical, and the flagellum multiarticulate. The 

 last joint of the tail is centrally very convex, but the 

 outer margin, both laterally and posteriorly, is flattened, 

 and the terminal slit is considerably widened at its base ; 

 the extremities of the sides of the slit sometimes closely 

 approximating or touching each other ; the lateral ap- 

 pendages have the outer division rather smaller than the 

 inner. The dactylos of the feet is armed on its inside 

 with a strong tooth. Our figure c represents the head 

 seen from the front, the oral appendages are therefore 

 represented as foreshortened. 



In the young state, the sides of the terminal slit of the 

 tail gape to a considerable width at their extremities. 



Montagu and Leach found this species in company 

 with the preceding in great quantities, and Mr. W. 

 Thompson took it at Lahineh, in Co. Clare, Ireland. 



