102 



All the Indian species are small. They may be tabulated as follows, for 

 convenience of identification :■ — 



I. One jjiiir of epigastric crests present as usual ; exopodite of external niaxillipeds 

 as long as the ischium, which is longitudinally grooved on the ventral 

 surface : — 



i. Epigastric crests with trenchant edge ; epibranchial tooth prominent ; 

 6th abdominal segment of adult male as long as broad ; antennal 

 flagellum small but distinct ...... 



ii. Epigastric crests comparatively obtuse ; epibranchial tooth small or 

 obsolescent : — 



1. Antennal flagellum vestigial, not visible without dissection; the 

 vertically-deflexed portion of the front forms a distinct facet 



2. Antennal flagellum small but distinct ; no well-defined frontal 

 facet : — 



«. Exopodite of external maxilli))eds with or without flagellum ; 



epigastric crests distinct ..... 



b. Exopodite of external maxillipeds without a flagellum ; epi- 



gastric crests indistinct ..... 



II. Two pairs of epigastric crests, one pair in rear of the other ; exopodite of 



external maxillipeds only about half as long as the ischium, which is not 



longitudinally grooved ; no antennal flagellum .... 



Or, the species of Phricotelphusa may be tabulated thus : — 



I. Exopodites of external maxillipeds non-flagellate : — 

 i. One pair of epigastric crests : — 



1. Antennal flagellum small but visible : — 



a. Epigastric and post-orbital crests thin and sharp 



b. Epigastric and post-orbital crests indistinct 



2. Antennal flagellum vestigial and completely hidden under the 

 front ........ 



ii. Two pairs of epigastric crests ...... 



II. Exopodites of external maxillipeds sometimes flagellate, one pair of epigastric 

 crests which are rather obtuse ; antennal flagellum small but visible 



P. callianira. 

 P. eleffdtix. 



o 



p. soseii- 

 p. campestri.s. 



p. cririiiiferd. 



P. callianira 

 P. campesfrix. 



P. eleganx. 

 P. cariniferu . 



P. oaaeii. 



The subgenus Phricotelphusa graduates into the next subgenus Liotelphusa 

 by way of P. campeslris and P. gageii. In campestris the epigastric and post- 

 orbital crests are indistinct ; in gageii the exopodite of the external maxillipeds 

 may be flagellate. 



28. Paratelphusa (Phricotelphusa) callianira, de Man. (Fig. 62.) 



Telphusa callianira, de Man, Journ. Linn. Soc. Zool., XXII., 1.SS7, p. 96, pi. vi., figs. 1-3. 



Potamon {Potamon) callianira, Mary J. Rathbun, Nouv. Archiv. du Museum (4), VI., 1904, p. 303 {uhi lit.). 



Carapace squarish and tiattish, its length exceeding three-fom'ths its 

 greatest breadth, its depth less than half its length ; its surface is finely pitted 

 under a lens, and the vicinity of the lateral borders is beset with fine oblique 

 ripples that pass across from the side-walls. 



Cervical groove well graven only where it defines the mesogastric area 

 posteriorly, elsewhere very broad and vague, and running towards the lateral 



