R. DOUGLAS LAURIE—BRACHYURA. 439 
Localities. Station I. B, 4 g [51-54], 5 @ [55-59]; Station I.H, 1 ¢ 
probably adult [60]; Station I.G,1¢ [61],1 9 [62]. 
Remarks. The length of the carapace varies in the males from 11 to 16 mm. 
and from 11 to 17-5 mm. in the females. 
In both sexes it is sometimes the right and sometimes the left cheliped 
which is the larger, thus it is the right in four of the males and three of the 
females, and the left in the remainder of the specimens. 
I do not share Alcock’s doubt as to the distinctness of this species from 
T. chaptalu. Points of difference are as follows :— 
1. As pointed out by Alcock, the teeth of the antero-lateral border are in 
T. poissoni acute, and the last tooth is more spiniform and more prominent 
than the others. 
2. As pointed out by Nobili, the fourth tooth of the antero-lateral border is 
in 7, potssonii much smaller than the others. 
3. Alcock notes that the teeth of the anterior border of the arm are in 
T. poissonit acute; this is so in the present specimens, in which they are 
three or four in number. So also are the other teeth of the cheliped acute, 
and this is conveniently seen in the case of the tooth on the upper surface of 
the propus, in front of the carpo-propal articulation. Borradaile (1902 (1), 
p. 201) records, however, a male from Suvadiva which “ has the spines on the 
fore edge of the meropodite of the cheliped blunt,” as in 7. chaptalit. 
4. In place of the somewhat granular eminence on each antero-lateral 
portion of the gastric region in 7. chaptalii there is in 7. potssondi a short 
transverse granular ridge. 
5. The present specimens contrast with those from the Gulf of Manaar 
placed by me (Laurie, loc. cit.) under 7. chaptalit in the shape of the front ; 
its outer limit is well marked and rounded in the present specimens instead 
of gently sloping, so that the anterior frontal margin is fairly straight trans- 
versely. 
6. The hinder edge of the propodite of the last leg bears in 7. povssonn 
several spinules, of which there is no trace in 7. chaptalii. This difference is 
emphasized by Borradaile. 
7. The setze of the dorsal surface of the carapace are longer in the present 
specimens of 7. potssonii than in the Gulf of Manaar examples of 7. chaptalii 
mentioned above ; the difference, though not great, is constant. 
8. An additional point is the red coloration (spirit-specimens) of the upper 
mero-carpal point of articulation ; this concerns both the articular process of 
the carpus and the margin of the articular cavity of the merus, and appears 
as a conspicuous red dot in a dorsal view of the animal as it lies in a position 
of rest. Colour in spirit is no doubt elusive, but in the present instance the 
red spot is clearly seen in all the specimens, but not to be made out at all in 
a series of 22 specimens of J. chaptalii from Gulf of Manaar which I have 
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