EUCHLANID^. 41 



It mucli resembles a Euchlanis ; the lorica is in two plates, the dorsal, arched and 

 expanded at the sides, which are bent sharply back underneath. The ventral plate is 

 flat, and fills up the gap between the bent-back edges of the dorsal plate. In front, and 

 behind, the lorica is cut away by a half-nioon-shaped scollop, and is prolonged at the ex- 

 tremities of each semicircular edge into spines, of which the posterior pair is the longer. 

 The foot is four-jointed, and bifurcate. There are no eyes ; but, on the spots where they 

 should be, are two small hollow protuberances, from which rise two long movable 

 antennffi, with bristle-like ends, stretching forward beyond the corona. Two smaller 

 bristles spring from the spot which in Euchlanis bears a spur-like antenna. Dr. Joseph 

 is of opinion that the young male and female are precisely alike in structure ; but that 

 the male gradually loses the whole of the digestive tract, as it approaches maturity. His 

 account leaves it doubtful whether he is describing a succession of changes that he has 

 watched in the same individual, or whether he is detaUing inferences that he has drawn 

 from various individuals observed at different times. Dr. Joseph gives no figure of the 

 animal. 



Length, ^l inch. 



Genus DAPIDIA, Gosse (170). 



GEN. CH. A genus of the Euchlanidro, whose ventral plate is wanting ; the turned- 

 in lateral edges of the dorsal plate heing united only bij a flexible and expansible skin. 



Dapidia steoma, Gosse (170), (PI. XXXI., fig. 35). 



[SP. CH. Outline ovate, dorsum high, rounded ; lorica much exceeding the 

 viscera in ividth, and turned in beneath ivith straight margins ; viscera, i^rotected exclu- 

 sively by membrane. 



Dr. Hudson (vol. ii. p. 93) has alluded to my opinion that certain species of Eu- 

 chlanis are generically separable by the character of wanting a ventral plate ; the lateral 

 edges of the lorica, which turn in beneath, being united only by flexible and expan- 

 sible skin. My esteemed colleague differs from me ; and, on a matter so exceedingly 

 delicate and difficult to determine, I may be m the wrong. But I am not convinced ; 

 and I hope it is not inconsistent with modesty or friendship to record my own judgment.' 

 The species, I think, is midescribed, whatever its generic place. 



The lorica is shaped (if I may use so homely a comparison) like a boat turned 

 bottom up, her bows cut off sharp, her gunwale curved-in, and no keel. Suppose the 

 cavity of the boat to be loaded, half-ivay up, with goods [the viscera], and a tarpaulin 

 [the common skin] to be spread over all, but higher in the middle than at the sides ; the 

 head-mass, of livuig fleshy organs, to be thrust out at the tnuicate and open bow, filling 

 it ; and the foot and toes to represent the rudder ; — a fair idea will be conceived of this 

 fine form. There are no foot-setse. 



It may easily be supposed to possess a ventral plate. But what looks like one, on a 

 (nearly) lateral view, is the edge of the farther incurved side of the lorica ; when 

 viewed from behind, there is no lateral infold or sinus running longitudinally. I have 

 seen numerous examples. 



Length, ^'^ inch. Habitat. Lacustrine. P.H.G.] 



Cathypka diomis, Gosse (170), (PI. XXXI. fig. 38). 



[SP. CH. Generally like C. luna, but lorica, much elevated behind, and ending there 

 abruptly ; followed by a wide hemispheric joint ; toes slightly blade-shaped ; claw iwo- 

 shouldered, short, recurved. 



A rather remarkable little form. The lorica, broadly ovate, is unusually arched, and 

 abruptly truncate just behind its greatest elevation ; whence another wide roimded plate 



' It was with reference to Euchlanis dcflcxa that I differed from Mr. Gosse ; I have not seen 

 Dapidia stroma. 



