eee NOME oO CHRUS DACH A DE CAP ODA 
INS PHABsINDIAN MUSEUM. 
VI. INDIAN CRANGONIDAE. 
By STANLEY Kemp, B.A., Superintendent, Zoological Survey 
of India. 
(Plate VIII.) 
The number of Crangonidae known from Indian seas has been 
considerably increased by recent work in shallow water on various 
parts of the coast. In dealing with the additional material that 
has come to hand I have thought it useful to include references to 
all the known Indian forms and to construct keys to facilitate the 
identification of the species of Pontophilus and Aegeon. 
Six species hitherto unknown are described, all belonging to 
the genus Pontophilus, while, thanks to the assistance of Dr. W. T. 
Calman, I have been able to rectify certain errors in the nomen- 
clature of two species of A egeon. 
In a previous paper in this series '! I expressed the view that 
Philocheras, Stebbing (= Cheraphilus, Kinahan, partim) could not 
be sustained asa distinct genus, but must be merged in Pontophilus. 
In examining the new forms of this genus a point hitherto over- 
looked has come to light, namely, that in certain species there 
are considerable differences between the sexes in the form of the 
pleopods. The modifications of these appendages are not only of 
interest as evidence of the affinities of the different species, they 
also, as it appears to me, afford a valuable clue to the origin of 
the various genera of the family and point to lines of descent 
very different from those suggested by Ortmann in 1890. I have 
thought it best to discuss the structure of these appendages and the 
phylogenetic conclusions which may be derived from them under a 
separate heading at the end of the paper. 
In all eighteen species of Crangonidae are now known from 
Indian waters, ten belonging to the genus Pontophilus, six to Aegeon 
and one each to Prionocrangon and Crangon. 
Genus Pontophilus, Leach. 
The six undescribed Indian species of this genus were obtained, 
two from Kilakarai at the northern end of the Gulf of Mannar 

1 Rec. Ind. Mus., V1, p. 5 (1911). 
