252 



5- Carapace quadrangular P. pcctiiiicohts 



Carapace subcircular 6 



6- Dactylus of ext. maxillipeds considerably overreaching propodus. 



Chelipeds and legs nearly hairless . . P. afflnis 



Dactylus of ext. maxillipeds not much overreaching propodus. 



Chelipeds and legs hairy. Species from Japan P. pholadis ^) 



7. Dactylus of ext. maxillipeds by far not reaching to end of 



propodus 8 



Dactylus of ext. maxillipeds reaching to end of propodus . . 15 



8. Carapace pubescent. Propodus of ext. maxillipeds not longer 



than carpus P. villosii/us 



Carapace glabrous • 9 



9. Walking legs hairy. 10 



Walking legs naked 11 



10. Carapace subcircular, vaulted. Walking legs rather robust . . P. luactricolus 

 Carapace angular, with a prominent lobe in the middle of the 



lateral margin P. trichopiis 



11. Dactylus of ext. maxillipeds not one- fourth of length of propodus P. rotixi 

 Dactylus of ext. maxillipeds longer than one- fourth of length 



of propodus 12 



12. Inner (posterior) margin of merus-ischium of ext. maxillipeds 



strongly concave 13 



Inner (posterior) margin of merus-ischium of ext. maxillipeds 

 straight 14 



13. Propodus of ext. maxillipeds very long and narrow . . . . P. kamensis 

 Propodus of ext. ma.xillipeds shorter and broader P. glaócrriiuus 



14. jMerus-ischium of ext. maxillipeds broad, length about lY, times 



its length P. cardii 



Merus-ischium of ext. maxillipeds longer, length more than 



twice its breadth . P . socuts 



15. Carapace large, globular, with some large pits, tomentose, 



branchio-cardiac grooves distinct Propodus of ext. maxillipeds 



flattened and broad P. edwardsi 



Carapace small, without distinct markings. Propodus of ext. 

 maxillipeds decreasing in breadth distally 16 



16. Propodus of ext. maxillipeds nearly as long as carpus . . . P. kutcnsis 

 Propodus of ext. maxillipeds longer than carpus P. oöcsus 



17. Dactyli of 2^ pair of walking legs the longest 18 



Dactyli of 2'' pair of walking legs not longer than those of 



I-"' and 3'^ pair 19 



i) Accovding to Adensamer P. pisoides Ortmann is identical with DE Haan's species. Unfortiinately not a single one of tJie 

 more than twenty specimens examined by de Haan is now extant in the Leiden Museum. 



104 



