Crustacea Decapoda and Stomatopoda. 245 
The chelipedes of the male are scarcely longer than the breadth of the carapace. 
The upper edge-of the merus is granular and terminates in a blunt and obscure sub- 
terminal lobe. Both inferior margins are granular and the outer surface bears num- 
bers of small rugae arranged transversely. The carpus is rugose above ; the internal 
tooth is very strong and behind and beneath its apex there are one or two conspicuous 
tubercles. The chela is slender, the depth of the palm being only about one and a 
half times the length of the upper border. The outer surface is slightly rugose proxi- 
mally and bears numerous punctae, some of which form a conspicuous, median, longi- 
tudinal row. The fingers are nearly twice the length of the upper border of the palm ; 
they are strongly fluted and pitted and meet throughout their length when the claw 
is closed, the tips crossing each other. 
The second walking legs, which are the longest, are about one and three quarters 
the length of the carapace. 
The abdomen of the male is very broad and is irregularly pitted. The segments 
increase successively in length, that of the sixth being only one third its basal breadth ; 
the seventh segment is simply triangular, with a slightly sinuous proximal border, 
and its length is contained about one and three quarter times in its basal breadth. 
In the female the last abdominal segment is still more broadly triangular, its length 
being scarcely more than one half its basal breadth. The eggs are extremely large,- 
each being from 2"0 to 2 5 mm. in diameter (text-fig. 5). 
The species is described from two specimens, a male and a female, the latter 
ovigerous, but lacking the chelae. In the male the carapace is 14-6 mm. in length 
and 17-8 mm. in breadth; in the female it is 17-3 mm. in length and 19-9 mm. in 
breadth. The female in life was dull olive brown with bright red eggs ; the male was 
of a distinctly blue shade of grey, a colour that has not apparently altered after nine 
months' preservation in spirit. 
P. anacoluthon appears in some measure to form a link between the subgenera 
Potamon and Geotelphusa, agreeing with the former in the presence of a strong epi- 
branchial tooth and with the latter in the almost complete suppression of the post- 
orbital crests. It does not seem to possess close affinities with any species hitherto 
described. 
The two specimens, types of the species, were found by Dr. Annandale on the 
Peak at Hongkong, under large .stones at the edge of a small stream at an altitude of 
1000 ft. They are preserved in the Indian Museum and bear the number 9475/10. 
Potamon (Geotelphusa) dehaani (White). 
1905. Potamon {Potamonautes ' ) dehaanii, Rathbun, Nouv. Arch. Mus. Paris (4), VII, p. 204, 
pi. xviii, fig. 4. 
1907. Geothelphusa Dehaani, Stimpson, Smiths. Misc. Coll., XLIX, p. 112 [nee. syn.). 
1916. Potamon {Geothelphusa) Dehaanii, Parisi, Atti Soc. Ital. Sci. Nat.,'L,V, p. 163. 
The collection contains numerous specimens from Japan. The species was com- 
mon in hill streams, in ponds and in irrigation channels in the country round Lake 
' Presumably a clerical error for Geothelphusa, but repeated in a footnote under Stimpson's record. 
