GREGARIOUS CRUSTACEA PROM CEYLON. 
5 
1902. Alpheidce , De Man, Kiikenthal’s Ergebnisse, Abh. Senc- 
kenb. Gesellschaft, vol. XXV., pt. 3, p. 861. 
1903- Alpheidce , G. M. Thomson, Trans. Linn. Soc. London, 
Zook, vol. VIII., pt. 11, p. 436. 
ALPHEUS , Fabricius. 
1798. Alpheus , Fabricius, Supplementum Ent. Syst., p. 404. 
The species Alpheus socialis , Heller, as described and figured 
by Mr. G. M. Thomson in the work above-mentioned, shows 
remarkable variability in regard to the frontal portion of the 
carapace and the shape of the large cheliped. It is a question, 
however, whether the specimens examined may not have belonged 
to more than one species. 
ALPHEUS HETEROGHELIS, Say. 
1818. Alpheus heterochelis , Say, Journ. Acad. Nat. Sci. Philad., 
vol. I., p. 243. 
1825. Athanasus edwardsii , Audouin, Explic. planches de 
Savigny, pi. 10, fig. 1. 
1884. Alpheus edwardsii , Miers, Voyage of H.M.S. Alert, 
1881-1882, p. 284. 
1888. Alpheus edwardsii , Bate, Challenger Macrura, Reports, 
vol. XXIV., p. 542, pi. 97, fig. 1. 
The solitary specimen obtained of this species was described 
by Dr. Willey as a blue-green Alpheus , taken among the tubes of 
the tubicolous amphipods at Lake Negombo, The blue-green tint 
on its arrival in England was no longer visible, the general 
colouring being quite pallid, but diversified by a large squarish 
patch of bright orange in the middle of the carapace, and a 
similar hue along the back of the pleon. The larger cheliped 
is on the left; both limbs are of a dusky orange, with a faint 
bluish line here and there. The length of the specimen is about 
25 mm. 
It cannot, I think, be distinguished from the species described 
by Miers in the reference given above, and the name here 
assigned to it really rests on his authority. Otherwise I should 
have been inclined to adopt for it the name Alpheus avarus , 
Fabricius, in agreement with Spence Bate’s observation that 
“ Alpheus avarus , Fabricius, appears to have no strongly marked 
features separating it from Alpheus edwardsii,” But Miers, 
