Ph. sedcntaria, Forskål. 



352 CARL BOVALLIUS, AMPHIPODA HYPERIIDEA. I. 2. PHRONIMII)^. 



Phroiiima. 



SO called species are closely related to each other and show transitions, so that I think 

 they ought to be regarded as varieties rather than species. But as I liave found small 

 but constant differences even in the young of, for instance, Phronima sedentaria as 

 compared with Ph. atlantica, I at present retain the following seven species in the hope 

 that I may soon have access to living specimens and be able to study the question 

 thoroughly. 



Phronima sedentaria, Forskål. 



» custiis, Risso. 



Bivovia zanzara, Cocco. 

 Phronima Borneensis, Spence Bate. 



» novazealandice, Powell. 



)i yieozelanica, Thomson and Chilton. 



» atlantica, Guérin. 



)) solitaria, Guérin. ) . , 



, , o ) ^ Ph. solitaria, (juerin. 



» megaioaus, ötebbing. ( 



» pacifica, Streets. 



» spinosa, C. Bovallius. 



« Colletti, C. Bovallius. I 



» hucephala, Giles. > = Ph. Colletti, C. Bovallius. 



« Diogenes, A. Chun. | 



» tenella, Stebbing. 



Characteristics used for distinguishing the species in the genus Phronima. 



1. The length of the head. 



2. The fifth pair of perajopoda being longer — or shorter than the fourth. 



3. The length of the carpal pi'ocess in the fifth pair in relation to the tubercle on the 

 under margin of the carpus, and in relation to the metacarpus. 



4. The tubercle on the under margin of the carpus being undivided — or divided into 

 two or more points or teeth. 



5. The relation of the length and breadth of the carpus in the fifth pair. 



6. The femur in the seventh pair being about as long as, or longer than, that in the 

 sixth. 



7. The hind corners of the pleonal segments being rounded, — sharp-pointed, — or 

 produced into long processes. 



8. The inner ramus of the second pair of uropoda being shorter — or longer than 

 the outer. 



