246 ZOOLOGY OI? THE FAR EAST. 



Biwa. It is said to enter the lake itself, but Dr. Annandale could find no specimens 

 there. In wet weather it often travels a considerable distance from water and one 

 individual was found in the streets of Otsu. The precise localities of the specimens 

 are (i) from hill streams and garden paths near Otsu ; (ii) from irrigation channels at 

 Hikone on the western shore of L,. Biwa ; (iii) from hill streams above Sakamoto on 

 the eastern shore of L- Biwa ; (iv) from a small lake at Komatsu on the same shore of 

 the lake. 



In the largest male, a specimen with carapace 30 mm. in breadth, the right chela 

 is enormously enlarged, 31 -5 mm. in length, with very widely gaping fingers. 



Subfamily GECARCINUCINAE. 

 Genus Paratelphusa, Milne-Edwards. 



1910. Paratelphusa, Alcock, Cat. Indian Decaf. Crust., I, fasc. ii, p. 70. 



Subgenus Paratelphusa, Wood-Mason. 

 Paratelphusa (Paratelphusa) tridentata, Milne- Edwards. 



1905. Potamon (Paratelphusa) tridentatus, Rathbun, Nouv. Arch. Mus. Paris (4), VII, p. 234, 

 pi. xi, fig. 2. 



A number of distinct species were at one time confounded under this name : the 

 series so labelled in the Indian Museum collection contains, in addition to the true 

 P. tridentata, examples of P. convexa, de Man, P. mamlata, de Man and P. oxygona, 

 Nobili. In determining this material I have derived much assistance from de Man's 

 papers, particularly that pubhshed in 1879,' as well as from Miss Rathbun' s key and 

 fuU references to the literature. 



The specimens of P. tridentata in the present collection are five in number, all 

 collected by the late Dr. W. C. Hossack in Java. There are three males and a female 

 from Buitenzorg Gardens, alt. 300 ft., and one female from Garoet, alt. 3000 ft. The 

 carapace of the largest individual, a female, is 42 mm. in breadth. 



The species is recorded from Borneo, Java, Sumatra and the neighbouring islands. 



Paratelphusa (Paratelphusa) convexa, de Man. 



1905. Potamon (Paratelphusa) convexus, Rathbun, Nouv. Arch. Mus. Paris (4), VII, p. 237. 



Three specimens were obtained by Dr. Hossack in Java in company with ex- 

 amples of the preceding species. A male and female with carapace respectively 27 

 and 28-5 mm. in breadth were found in Buitenzorg Gardens and a female of similar 

 size at Garoet. The specimen from the latter locality differs from the others in 

 colour, being rather closely mottled with deep purple on a dull olive ground. 



P. convexa is known from Timor, New Guinea, Borneo, Java and Nias. 



1 De Man, Notes Roy. Zool. Mus. Leyden, I, p. 6i (1879). 



