1Qt6. | S. Kemp: Notes on Crustacea Decapoda. 381 
race that he recognises, the difference between the European and 
Japanese races consisting solely in the greater variability exhibited 
by the latter. 
The Indian specimens do not show any marked variation, but 
the series is small. And even should their form prove -constant, 
it is useless to speculate on the precise status of the different races 
until some general consensus of opinion on the Japanese forms has 
been reached. 
Crangon crangon appears to be very rare on the Indian coasts ; 
the only specimens in the Museum are the following :— 
6412 Akyab, Arakan coast. FF. Stoliczka. 5, 35-52 mm. 
THE STRUCTURE OF THE PLEOPODS IN PONTOPHILUS. 
The recognition of the fact that in certain species of Pontophilus 
there are often marked differences between the sexes in the form 
of the pleopods, and that the species themselves also differ to a 
great extent in the development of these appendages, has led me 
to re-examine the material available in the Museum collection. In 
the Indian Museum twenty-one species of the genus are represented, 
a very considerable proportion of those that are known; but, un- 
fortunately, in the case of thirteen only do we possess examples of 
both sexes. 
Although in the development of the pleopods there is a certain 
amount of intergradation, it is possible roughly to classify the 
species according to the development of these appendages into 
five groups :— 
Group I. 
- Endopod of last four pairs of 
| pleopods well developed in both 
) sexes, with conspicuous appendix 
' interna. 
P. spinosus, Leach, P. abysst, Smith, and P. occidentalis, 
Faxon, represented in the collection by female specimens only, 
doubtless also belong to this group. 
P. norvegicus, M. Sars 
P. gracilis, Smith 
P. brevirostris, Smith 
Group II. 
Endopod of last four pairs of 
pleopods comparatively well deve- 
loped in male, reduced in female. 
P. sculptus (Bell) Appendix interna present in male 
P. incisus, sp.nov. on all four pairs, but somewhat 
P. australis, Thomson | rudimentary on the last; in female 
present on 2nd and 3rd pairs, rudi- 
mentary on 4th and absent from 
. 5th. 
P. chiltoni, Kemp, known from female specimens only, also in 
all probability belongs to this group. 
