254 Records of the Indian Museum. [Vora Ws 
assent. Potamocarcinus and its relatives seem to me to fall in 
with my series of Paratelphusine or Gecarcinucine, though they 
certainly have some common peculiarities of their own. 
(4) The close relation of Potamon and Paratelpbhusa. In my 
memoir of the Indian Potamonide I have given the reasons 
against this association. 
In Dr. Ortmann’s scheme Acanthotelphusa is recognised as a 
distinct subgenus closely related to Evimetopus. ‘This is, I am 
sure, a natural arrangement; but nothing supports Dr. Ortmann’s 
conjecture that Acanthotelphusa has any specially close relation tc 
Potamocarcinus. 
In Miss Rathbun’s scheme Gecarcinucus is certainly quite out 
of perspective. This genus, so far from being anything extra- 
ordinary, can with difficulty be dissevered from Paratelphusa. 
For my own part I should like to eject the Trichodactylinee 
and to see Deckenia subordinated to the Potamonine, and Potamo- 
carcinus and its relatives subordinated to the Paratelphusine, 
leaving only two subfamilies of Potamonide; but at the present 
moment I only propose to re-arrange Miss Rathbun’s scheme 
slightly, and to re-characterize some of her subfamilies, as exhibited 
in the following synopsis and key :— 
SYNOPSIS OF SUBFAMILIES OF POTAMONIDA. 
( Dactylit of crawling-legs not spinose: 
| merus of external mazxillipeds 
elongate, its outer border being 
longer than that of the ischium 
measured from the fork of the 
exopodite. Mandibular palp of 
three distinct joints, its terminal 
joint simple. Abdomen of male 
broadly triangular, the 6th segment 
I< when separate being several times 
broader than long i 
Dactyli of crawling-legs spinose: 
merus of external maxillipeds not 
elongate: mandibular palp of 
either two or three joints, its 
terminal joint either simple or 
bilobed: 6th segment of male 
abdomen variable, but never more 
_\ than twice as broad as long ee 
(Efferent branchial channels pro- 
| duced to the edge of the front, 
| entrenching on and somewhat ob- 
4  scuring the epistome, cramping the 
| antennee, and so much contracting 
L 
‘TRICHODACTYLIN 4. 
the antennular fossze that the an- 
2 tennules foldalmost longitudinally. 
