KONGL. SV. VET. AKADEMIENS HANDLINGAK. BAND. 21. N:0 5. 



A. The first pair of antenna? straight, the first joint of the flagellum large, the 

 following few in number, terminal: 

 a 1. The head small, not tumid. 



aa 1. The first joint of the flagellum of the first pair of antennas styli- 



f'orm, not tumid 1. Tyronidse. 



aa 2. The first joint of the flagellum of the first pair of antenna? high, 

 tumid. 



aaa 1. The seventh pair of pereiopoda not transformed 2. Lauceolida?. 



aaa 2. The seventh pair of pereiopoda transformed 3. Vibilidse. 



a 2. The head large, tumid. 



aa 3. The first, joint of the flagellum of the first pair of antenna? 

 tumid. 



aaa 3. The seventh pair of pereiopoda transformed. _ __. 4. Cyllopodida?. 



aaa 4. The seventh pair of pereiopoda not transformed 5. Paraphrouimidie. 



aa 4. The first joint of the flagellum of the first pair of antenna? 



styliform, not tumid _ 6. Thauniatopsidie. 



a 3. The head with the pereion transformed into a balloon-like bladder 7. Himonectida?. 



B. The first pair of antenna? straight, the first joint of the flagellum large, the 

 following many in number, filiform (cf 1 ), terminal. 

 b 1. The uropoda normal, with rami. 



bb 1. The mandibles with palp. 8. Hyperiidae. 



bb 2. The mandibles without palp 9. Phroniiuida?. 



b 2. The uropoda transformed, without rami. Last five pairs of pereiopoda 



prehensile organs 10. Anchylouierida?. 



C. The first pair of antenna? curved, the first joint of the flagellum large, the 

 following few in number, subterminal. Second pair angularly folded (a 71 ). 

 C 1. The femur of the sixth pair of pereiopoda not operculiform, the rest 

 of the leg articulating terminally. 

 CC 1. The first pair of antenna? fixed at the anterior side of the head 11, Euphorrida?. 

 CC 2. The first pair of antenna? fixed at the inferior side of the head. 

 CCC 1. The anterior part of the head very shortly produced, or 



not produced 12. Tryphienidse. 



CCC 2. The anterior part of the head produced into a rostrum, 



longer than half the rest of the head 13. Oxycephalidse. 



