232 ZOOLOGY OF THE FAR EAST. 



In young examples, as in it. japonicus, the antero-lateral borders of the carapace 

 are much straighter than in adults and there is less hair on the hands. In a male 

 with carapace 15 mm. in length the hair is restricted to the outer surface of the 

 chela and it is completely absent in all specimens under 12 mm. in length. The four 

 teeth on the front are very sharply pointed in adults, but much blunter in young in- 

 dividuals. 



Eriocheir rectus ' (Stimpson) is perhaps merely a synonym of this species. It was 

 described from a specimen 0-92 ins. in length and is chiefly characterised by its 

 straighter lateral margins and blunter frontal lobes, thus closely resembling the 

 young of E. sinensis. 



Dr. Annandale informs me that this is the common edible crab of Shanghai and 

 is to be found on sale in all the village markets round the Tai Hu, where it is chiefly 

 captured in narrow creeks. Doflein * records the species from Shasi on the Yang-tse- 

 kiang, 1300 kilometres from sea, and also from brackish water in the neighbourhood 

 of Shanghai. 



Eriocheir leptognathus, Rathbun. 



1914. Eriocheir leptognathtis, Rathbun, Proc. U. S. Nat. Mus., XLVI, p. 353, pi. xxxiii, 

 figs. 2, 3. 



To this species I refer a small male with carapace 91 mm. in length and 9-6 mm. 

 in breadth. It agrees on the whole very well with Miss Rathbun' s description. The 

 edge of the front is almost straight, only very obscurely trilobed, the postero-lateral 

 margins of the carapace are parallel rather than convergent and the hindmost tooth of 

 the antero-lateral border is extremely small and inconspicuous. The outer surface of 

 the palm is bare, as in the type, but there is a dense patch of woolly hair on the inner 

 side, extending on to the base qf both fingers. 



The granulate ridge, anteriorly concave, that runs inwards from the hindmost 

 tooth of the antero-lateral margin is well marked ; it is finer and less elevated than in 

 E. japonicus or E. sinensis and in front of it there is no trace of the comparatively 

 deep depression found in those species. There is, moreover, a noticeable distinction 

 in the size of the eyes. If specimens of similar dimensions be compared it will be 

 seen that the cornea is much smaller in E. leptognathus than in the two allied species 

 and is decidedly narrower than the basal part of the stalk. The most obvious 

 character in which the species differs from other members of the genus is, however, 

 the presence of only three instead of four teeth on the antero-lateral margin of the 

 carapace ; this feature seems to have escaped Miss Rathbun' s attention though it is 

 clearly shown in her figure. 



The single specimen was found in company with young E. sinensis in the 

 Whangpoo River, between Shanghai and Woosung at a depth of 5J to 7J metres. It 

 was found in pure fresh water. 



The female described by Miss Rathbun was loô mm. in length and no mm. in 

 breadth and was obtained at Shanghai. 



1 Eriochirus rectus, Stimpson, Proc. Acad. Nat. Sci., Philadelphia, X, p. 103 (1858) and Smiths. Misc. Coll., XI<IX, 

 p 125 (1907). 



2 Doflein, Abhandl. K. Bayer. Akad. Wiss., XXI, p. 665 (1902). 



