318 AMPHIPODA NORMALIA. 



the tubercle on the carpal process more tooth-like in form, and 

 that upon the propodos less prominent and smooth. 



Hah. Nice ; in the cavities of Medusae {liisso, Desmarest). 



Risso describes this species as being whitish. In all other respects 

 it corresponds very closely with P. sedentnria. 



The descriptions given by authors of this and the preceding species 

 appear adapted for cither. Without ha\'ing examined the typical speci- 

 mens, I can only assume them to be as here named — if, indeed, they 

 are not varieties of the same species only. 



3. Phronima Bomeensis, n. s. (Plate LI. fig. 3.) B.M. 

 Phronima Atlantica, White, Cat. Crust. B. M. 1850. 



This species resembles P. cnstos in the size of the chelate develop- 

 ment of the third pair of pereiopoda and in the fonu of the tubercle 

 on the fixed ramus, and P. sedentaria in the form of the crenu- 

 lated tubercle on the moveable ramus. 



I can detect no other variation of form in these species from ^ciy 

 distant localities : and the union of the specific characters of both 

 the Western species in that from the Eastern Seas suggests the idea, 

 in spite of their distant habitats, that the three forms may be but 

 varieties of one species. 



Hah. Borneo. Presented to the British Museum by the Lords of 

 the Admiralty. 



4. Phronima Atlantica. (Plate LI. fig. 4.) B.M. 



Phronima Atlantica, Guerin-Meneville, Iconogr. pi. 25. f. 4; Mag. 

 Zool. el. vii. pi. 18. f. 1. 



Edwards, Hist, des Crust, iii. p. 93. 



Third pair of pereiopoda having two large tubercular teeth on the 

 inferior margin of the carpal or fixed process. 



Hah. S. Atlantic {Capt. Stanley). 



SubfamOy 2. PHEOSINIDES. 



Having the three posteiior pairs of pleopoda foliaceous and mem- 

 branous. 



This subfamily corresponds with Dana's second division Phkosi- 

 -sasM, exclusively of the genus Themisto. 



2. PHROSINA. 



Phrosina, Rissn, Hist. Nat. dc l' Europe 3Icrid. v. p. 91. 

 Dactylocera, Edu-ards, Atm. des Sc. Nat. xx. p. 293. 



Edtcards, Ann. des Sc. Nat. xx. p. 393 ; Hist, des Crust, iii. p. 89. 



Cephalon with the antero-superior margin laterally produced to an 



