232 ZOOLOGY OF THE FAR EAST. 
In young examples, as in .E. 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 02 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 leptognathus, 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 of 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 5|- to y\ metres. It 
was found in pure fresh water. 
The female described by Miss Rathbun was 10 6 mm. in length and 11 6 mm. in 
breadth and was obtained at Shanghai. 
1 EriocMrus rectus, Stimpson, Proc. Acad. Nat. Set., Philadelphia, X, p. 103 (1858) and Smiths. Misc. Coll., XI,IX, 
p 125 (1907)- 
2 Doflein, Abhandl. K. Bayer. Ahad. Wiss., XXI, p. 665 (1902). 
