100 



1'. Head without distinct frontal border; lateral borders wanting. Genital area longer 

 than broad 36- S. microcephahi G. and B. 



2. Antennae quite rudimentaiy. A tuft of hair near the base of each maxillula. 



Group: S. Leuchartii Sal. 

 including the following species: . . . 1. S. elegantulan. S])., 2. S. Atylin.s^., S.S.danica 

 n. sp. , 4. S. vestita u. sp. , 5. S. Leptocheiri n. sp. , 6. S. messinensis 

 n. sp., 7. S. chinensis n. sp., 8. S. antiUensis n. sp. 



2'. Antennae pretty well developed. No hair-tufts near the base of the maxillulae ... 3 



3. Erontal margin without expansion in the middle 4 



3'. Frontal margin with a flatly cup-shaped expansion in the middle . . 25. S. frontalis n. sp. 



4. Trunk covered with short hairs, 2- or 3-brauched at their basis 5 



4'. Trunk naked or with rather few, simple hairs 6 



5. Caudal stylets situated between the genital apertures. The trunk thickly covered 

 with hairs 9. S. Calliopii n. sp. 



5'. Caudal stylets situated behind the genital apertiu-es. Hair-covering less thick. 



10. S. irregularis n. sp. 



6. Trunk fastened to the host by a very short ventral thread . . . 11. S. paradoxa n. sp. 

 6'. Trunk never attached to the host 7 



7. Trunk-legs — if found — cylindrical, with two setae 8 



7'. Trunk-legs distinct, rounded eminences without setae . . . . 24. S. AcantlMzonis n. sp. 



8. Maxillipeds good-sized; their basal joint much longer than that of the maxillae ... 9 

 8'. Maxillipeds rather small; their basal joint not much longer than that of the maxillae. 



23. S. Didichice n. sp. 



9. Trunk-legs, if found, with short setae 10 



9'. One of the terminal setae of the trunk-legs remarkably long, about tlu-ee times as long 



as the leg 21. S. longipes n. sp. 



10. Genital area naked or with rather few and — as a rule — scattered hairs .... 11 

 10 '. Genital area provided on each side with a curved line of long hairs. 



15. S. Holholli n. sp. 



11. Genital area forming a solid plate 12 



11 '. Genital area for the most part thin-skinned, the more solid chitine forming a greater 



part of a ring 13 



12. Numerous hairs between the base of the maxillae and the maxillipeds. Genital area 

 with a number of scattered hairs 16. S. intermedia n. sp. 



12'. No hairs between the base of the maxillse and the maxillipeds. Genital area naked. 



17. S. capensis n. sp. 



13. No transverse list betAveen head and trunk behind the base of the maxillipeds. 



13. S. Argissce u. sp. 



