320 



— Distal process of 5th segment of pereopods I and II petaloid, broad, 



not tapering distally, almost rectangular 



5. Laxohyperia Vinogradov and Volkov, gen. n. 



7. Pereopods III and IV simple 8. 



— Pereopods III and IV with subchela formed by broadened 5th and 

 slightly curved virgate 6th segment 6. Parathemisto Boeck 



8. Pereopods III-VII approximately equal in length or III-IV slightly 

 longer than V and VI 1 . Hyperia Latr. 



— Pereopods V or V and VI longer than III and IV 



2. Hyperiella Bov. 



9. First two somites of pereon fused in sexually mature females and 

 males 12. 



— First three, four, or five somites of pereon fused in sexually mature 

 females; first two, three, or four somites fused in sexually mature 

 males 10. 



10. Pereopods V-VII approximately equal in length although pere- 

 opods VI may be somewhat longer than V or VII. Length of telson 

 approximately equal to width at base 10. Lestrigonus M.-Edw. 



— Pereopods V much shorter or much longer than pereopods VI and 

 VII. Telson very short 11. 



1 1. First three somites of pereon fused in both sexes. Pereopods V much 

 shorter than VI and VII 13. Hyperionyx Bowm. 



— First five somites of pereon fused in both sexes. Pereopods V signif- 

 icantly longer than VI and VII 12. Themistella Bov. 



12. Pereopods II with strong chela formed by process of strong 6th seg- 

 ment and claw. Pereopods III- VII prehensile 



14. Phronimopsis Claus 



— Pereopods II with weak chela formed by distal processes of 5th and 

 6th segments. Pereopods III-VII not prehensile 13 



13. Antennae II of females relatively long, curved. Mandibles with den- 

 ticulate cutting margin. Maxillipeds with well -developed inner lobe. 



Exopodite of uropods III with denticles on outer margin 



9. Hyperioides Chevr. 



— Antennae II in females rudimentary. Mandibles with smooth cut- 

 ting margin. Maxillipeds with rudimentary inner lobe. Exopodite of 

 uropods III with smooth outer margin 11. Hyperietta Bowm. 



1. Genus Hyperia Latreille, In Desmarest, 1823 



Desmarest, 1823: 138; Bowman, 1973: 5. 



Medium size crustacenas, 10-30 mm in length. 



The body is strong, with broadened pereon, especially in females. 

 All somites of the pereon are free. The head is large, spherical and 

 without rostrum. The eyes occupy almost the entire surface of the head. 



