410 PROCEEDINGS OF THE ACADEMY OF [1894. 



Geographical distribution: Fresh- water of the West Indies aucl 

 the Cape Verde Islands. —Mexico (Wiegmauu, Milne-Edwards, v. 

 Martens, Stimpson, Sharp) ; Nicaragua (Smith) ; Cuba (v. Martens) ; 

 Hayti (Kingsley) ; Jamaica (Newport); Dominica (Pocock); Mar- 

 tinique (Sharp); Tobago (Mus. Strassburg'*). — Cape Verde Islands: 

 San Nicolao (Newport); San Jago (Bate). 



7. Atya gabonensis Giebel, 1875. 



Alj'a i^aboriensis Giebel, Zeitscbr. f. d. gesammt. Naturwiss. (2), XI, 1875, 



p/53. 

 Euaiva sciilptilis Kolbel, Sitz. Ber. Acad. Wiss. Wien, vol. 90, 1, 1884, p. 317, 



p'l. 2, fig. 8, pi. 3. 

 Ayta sculptata Ortmann, Zoolog. Jahrb., V, 1890, p. 465. 



Geographical distribution: Gaboon (Giebel); Orinoco (Kolbel). 



8. Atya (Evatya) crassa Smith, 1871. 



Smith, 2 and 3 Eep. Peabody Acad. Sci., 1871, p. 95. 



Kolbel, Sitzb. Acad. Wiss., Wien, vol. 90,1, 1884, p. 318, foot-note. 



Geographical distribution : Nicaragua (Smith) ; Mexico : Presidio 



(Kolbel). 



Doubtful Species. 



Atya poeyi Guerin, Crust, in Ramon de la Sagra, Hist, de I'tle de Cuba, 1857, 

 p. 46, pl. 2. fig. 7.— Cuba. 



Caridina mexicana Saussure, Mem. See. Phys. Hist. Nat. Geneve, 14, 2, 1858, p. 

 463, pl. 4, fig. 26.— Mexico. 



Atyoida glabra Kingsley, Proceed. Acad. Nat. Sci., Philadelphia, 1878, p. 93 — 

 Nicaragua. 



Atya serrata Bate, Challenger Macrur., 1888, p. 699, pl. 119. fig. 2.— Cape Verde 

 Isl. : San Jago. 



These species may be the young of A. scabra or may belong to 

 Atyoida. 



Considerations concerning the geographical distribution of the 



Atyid(B. 

 Some species of Attjidce. were formerly considered to be marine 

 animals; there is now no doubt that this family contains only fresh- 

 water forms. This family is probably one of the most primitive 

 groups of Decapoda living in fresh- water, having immigrated at an 

 early geological period. 



Only two species, Caridina tvycki and gracilirostris, are recorded 

 by Weber^** as found in a few cases in brackish waters of Sumatra 



18 This locality is not yet published : there is one adult male fromTobago in 

 the museum at Strassburg. 



1^ Die Siisswassercrustaceen der Indischen Archipels. — Zoolog. Ergebn. 

 Eeise Niederl. Ost.-Indien., II, 1892, p. 542. 



