102 



7. Sub-median skeleton with two pairs of processes (second and tliird pairs) between the 

 bases of the maxillipeds. Terminal setae of the caudal stylets somewhat longer than 

 the basal joint of the maxillipeds 11. S. paradoxa 



7'. Sub-median skeleton mth only one pair of processes (second pair) between the bases 

 of the maxillipeds. Terminal setse of the caudal stylets scarcely the length of the 

 basal joint of the maxillipeds 8 



8. Basal joint of the maxillae without any prominent plate 16. S. intermedia 



8'. Basal joint of the maxillae with a prominent plate with spiniform marginal processes 



round the distal, inward and backward turning angle 17. S. capensis 



9. Terminal seta of the caudal stylets somewhat longer than the terminal seta of the 

 outer branch of the first pair of legs 12. S. ahyssi 



9'. Terminal seta of the caudal stylets a little or much shorter than the terminal seta of 

 the outer branch of the first pair of legs 10 



10. Terminal seta of the caudal stjdets at least four to six or eight times longer than the 

 stylets, and much longer than the secondary seta of the outer branch of the first pair 

 of legs 11 



10'. Terminal seta of the caudal stylets only about three times the length of the stylets 

 and not longer than the secondary seta of the outer branch of the first pair of legs. 



l.S. S. Argisste 



11. Terminal seta of the inner branch of the first pair of legs equal in length to, or longer 

 thau the distance between the base of the same leg and the end of its outer branch. 



14. S. Metopes 

 11 '. Terminal seta of the inner branch of the fii'st pair of legs somewhat shorter than the 



distance between the bases of the same legs and the apex of their outer branch. 



15. S. RolboUi 



12. First pail- of legs with a long seta at the apex of the single branch , none on the 

 outer process 18. S. Gitanopsidis 



12 '. First pail- of legs with two branches, the terminal setae of which are shorter than the 

 leg; a seta on the outer process 13 



13. Trunk not much larger thau the head, with setaceous hairs, proceeding two or (generally) 

 three together from tiny knots 19. S. Giardii 



13'. Trunk more than double the size of the head, with moderately thin, normal hairs. 



20. S. Bonnieri. 



About species 1 — 8: Group of Sphceronella Leuckartii. 



In seven species belonging to the genera Paratylus G. 0. Sars, Cheirocratus Norm., 

 Leptocheirus Zadd., Gammaropsis Lilljbg., Mieroprotopiis Norm, and Corophium Latr., taken 

 in Denmark, Sicily, Cuba and Hong-Kong, T have found parasites which bear a close resem- 



