120 Prof. J. Wood-Mason on the 



XV. — A Consiyectus of the Sjjecies of Paratelphiisa, an Indo- 

 Malayan Genus of Freshwater Crabs. By James Wood- 

 Mason, Professor of Comparative Anatomy, Medical Col- 

 legBj Calcutta. 



The genus ParateJphusa was established in 1855 by Milne- 

 Edwards for the reception of two new species of crabs, one of 

 which [P. sinensis) was supposed to liave come from the "China 

 seas," the other {P. tridentata) from New Zealand. 



Stimpson, in his preliminary account of the Invertebrata 

 collected during- the United-States expedition to the North 

 Pacific, records the occurrence of the former at Canton, 

 in brackish water ; and Heller (' Reise d. osterr. Fregatte 

 Novara,' zoologisch. Theil, Crustaceen, p. 34) gives Java as 

 a locality for the latter. 



Dr. E. von Martens (in 'Archiv fiir Naturgesch.' 1868, 

 pp. 18-22) states that he himself had collected specimens of 

 P. sinensis on the banks of freshwater streams at Bangkok 

 and Petshaburi, in Siam, and of P. tridentata at Sinkawang 

 in Western Borneo, at Surabaya in Eastern Java, and at Lahat 

 in Central Sumatra, and satisfactorily accounts for the mistake 

 in the localities given for the original examples of the species 

 by Milne-Edwards. 



In 1871 I myself described two new species, the one from 

 Upper Burmah and the othcrfrom the Gangetic valley, through- 

 out which it occurs from Hardwar (the point at which the great 

 river issues from the Siwalik Hills) far down into the delta, 

 where the water is brackish ; and I then pointed out that the 

 species resembled many Canceridfe, and differed from all the 

 rest of the Telphusida? in having the distal ends of the mero- 

 podal joints of the chelipeds armed with a sharp spine : not 

 only are they to be distinguished by the presence of tliis spine 

 and by being in other respects more like certain Canceridaj, 

 but also by the armature of the antero-lateral margins of the 

 carapace, the teeth of which in point of number and form 

 are as constant for the several species as are those of the 

 Portunida3. 



The following conspectus, giving short characteristics, which 

 it is hoped will suffice for the ready recognition of the different 

 forms in the mean time, is published in anticipation of fuller 

 accounts in my illustrated monograph of all the Telphusidas 

 of India and its dependencies. 



I am indebted to Dr. von Martens for specimens of the two 

 species collected by him. 



