NO. 10 



CRUSTACEAN METAMORPHOSES — SNODGRASS 



51 



cryptoniscus cuticle. The body has become a small cylindrical sac 

 (D) about one and a quarter millimeters in length in which all trace 

 of segmentation has disappeared. The eyes are gone, and all the 



Fig. 19. — Isopoda: Epicaridea. Life history of Danalia airvata Fraisse. (A, C-H 

 from Caullery, 1908; B from G. Smith, 1906.) 



A, first instar larva. B, second free larval stage, with hermaphroditic sex 

 organs containing small ovaries and large testes. C, larva with testes fully 

 developed. D, parasitic larva on crab. E, same, with proboscis elongated. F, 

 functional female stage, with testes degenerated, ovaries fully developed. G, 

 female containing brood sac. H, female in final stage. 



Mth, mouth ; Ov, ovary ; Prb, proboscis ; 2Prpd, second pereiopod ; Tes, testis. 



appendages have been cast ofif with the exuviae except a pair of small 

 hooklike second pereiopods {^Prpd) with which the parasite main- 

 tains its hold on the host. A small conical proboscis {Prb) bears the 

 mouth on its end. The testes, now that they have performed their 



