472 PROCEEDINOS OF THE NATIONAL MUSEUM. vol. xxxiii. 



Genus ORTHAGORISCICOLA Poche. 



Lsemargiis {L. muricatus) Kroyer, 1837, p. 487. 

 Orthagoriscicola {0. muricata) Poche, 1902, p. 13. 



Female. — Carapace trapezoidal or wedge-shaped, one-fourth wider 

 than long, much narrowed anteriorly, posterior margin scarcely 

 reentrant; posterior lobes very broad and evenly rounded; eyes 

 invisible; grooving on the dorsal surface indistinct; lateral margins of 

 the carapace coarsely toothed; its dorsal surface sparsely covered 

 with spines. Frontal plates fused with the carapace, but their out- 

 lines indicated by well-defined grooves. Second and third thorax 

 segments distinct,- free, without dorsal plates, and forming a narrow 

 waist joining the carapace and genital segment. Fourth segment 

 with a pair of dorsal plates covering half the genital segment, their 

 margin serrate. Genital segment enlarged, its dorsal plates wider and 

 longer than the carapace, and overlapping each other along the mid- 

 line, their margins serrate. Abdomen on the ventral surface of the 

 genital segment and entirely concealed, its lateral margins prolonged 

 into l)road laminae similar to those of Cecrops. Egg-tubes carried be- 

 tween these laminae and the dorsal plates of the genital segment as in 

 Cecrops, irregularly coiled and many times the body length. First 

 antennae three-jointed; second pair stout and uncinate; maxillj^e much 

 smaller than in Cecrops; mouth-tube about the same ; second maxilli- 

 peds stout and with a large terminal claw. All the swimming legs 

 biramose, but rudimentary and destitute of plumose setae; rami of 

 first two pairs two-jointed, of third and fourth pairs one-jointed and 

 enlarged into huge flattened laminae. 



Male. — Carapace similar to that of the female, but relatively shorter 

 and wider; thorax segments also similar; genital segment much 

 smaller, only two-thirds the size of the carapace, its dorsal plate fused 

 along the mid-line with a wide and shallow posterior sinus through 

 which the abdomen shows. The latter is small and subquadrangular; 

 anal laminae narrow and oblong. Appendages similar to those of the 

 female; second antennae and second maxillipeds longer and stouter; 

 third legs like the first two pairs, with two-jointed rami, but the fourth 

 pair are one-jointed and enlarged as much as in the female. 



(Orthagoriscicola, Ortharjoriscus, the generic name of its host, and 

 cola, inhabiting or dwelling upon.) 



This genus was established by Kr637er in 1837 upon a few female 

 specimens obtained from the sunfish, Mola rnola. He called the genus 

 Lsemargus, but that name had just been used earlier in the same year 

 for a fish genus, and so Poche in 1902 proposed as a substitute Ortha- 

 goriscicola, with a consequent change in the gender of the specific 

 name. 



This genus has been more fully described by the different investi- 

 gators than the preceding and also better illustrated. Kroyer (1837), 



