408 PROCEEDINGS OF THE ACADEMY OF [1894. 



b 2 . Rostrum with lateral keels ending by angles or short spines 

 on each side of the base of rostrum. 

 Cj. Carapace not sculptured with keels, but often punctate. 

 Third pair of legs (in the adult) without a 

 spine on the inferior margin. 

 d v Rostrum very short. Lateral keels ending in 

 front in angles, not in spines. 



A. brevirostris (3). 



d 2 . Rostrum longer. Lateral keels ending in front 

 •in spiniform angles. 

 e 1 . Merus of the first two pairs of pereiopoda 

 hairy. u 

 f x . Rostrum straight. 



?A. margaritacea (3). 



/ 2 . Rostrum bent downward. 



?A. robusta. 



e 2 . Merus of the first two pairs of pereiopoda 



not hairy (?) A. scabra (3). 



c 2 . Carapace strongly sculptured in front with keels. 



Third pair of legs on the inferior margin with a 



spine in adult specimens. 15 . . .A. gabonensis (1). 



a 2 . Rostrum as long as the antennal scale, upper margin with six to 



eight spines. Anterior part of carapace with numerous spines 



and spiny carinations [Subgenus : JEvatya Smith] 



A. (Evatya) crassa. 



1, Atya moluccensis de Haan, 1849. 



A. moluccensis de Haan, Faun. Japon. Crust., Dec. 6, 1849, p. 186. 



A. armata A. Milne-Edwards, Annal. Soc Entomo'l., France (4), IV, 1864, p. 

 149, pi. 3, fig. 3. 



A. armata v. Martens, Arch. f. Naturg., 34, 1, 1868, p. 47, pi. 1, fig. 6. 



A. moluccensis d. H., Miers, Annal. Magaz. Nat. Hist. (5), V, 1880, p. 382, pi. 

 15, fig. 3, 4. 



A. giistavi Ortmann, Zoolog. Jahrb., V, 1890, p. 467, pi. 36, fig. 9. 



A. dentirostris Thaliwitz, Abhandl. Mus., Dresden, 3, 1891, p. 26. fig. 7. 



A. moluccensis d. H., de Man, in Weber, Zoolog. Ergebn. Keis. Niederl. Ost- 

 Indien, II, 1892, p. 357, pi. 21, fig. 20. 



A. moluccensis d. H., Ortmann, Jenaische Denkschr., VIII, 1894, p. 10. 



Geographical distribution: Fresh- water of the Indian Archipelago. 

 — Sumatra (de Man, Ortmann); Java (A. Milne- Edwards, 16 Miers, 

 de Man); Batjan (Miers); Bali (Miers); Celebes (Miers, de Man, 



14 The differences between the New Caledonian species A. margaritacea 

 and robusta and the West Indian A. scabra are very doubtful, since the anterior 

 pereiopoda of the latter have the merus furnished with a few hairs. I suppose 

 that the locality given by Milne-Edwards for margaritacea and robusta is not 

 correct, and that there is no difference from A. scabra. (See below.) 



15 I think the differences of A. gabonensis and perhaps also of A. crassa 

 are not of specific value, but that they are differences of age: A. gabonensis 

 would be a very old state of A. scabra, but it may be that A. crassa is a distinct 

 species. 



16 A. Milne-Edwards records his specimens, 1. c, erroneously from the Philip- 

 pine Islands (see de Man, 1. c, p. 357, foot-note). 



