of the Genus Atya,from Celebes. 361 



capable of retaining a very considerable quantity of foreign 

 material (fig. 14). 



The carpos of the second pereiopod (fig. 10) is much 

 longer than that of the first ; it is almost uniformly cylin- 

 drical in shape, but swollen into a joint at its distal extre- 

 mity. The chelsB are similar to those of the first pair. 



The posterior three pairs of pereiopods are approximately 

 equal in size and terminated by sharp pointed claws armed 

 with short thorn-like hairs ; they are covered only with a 

 very sparse covering of hairs. The basal joint of each 

 pereiopod except the last bears one or two very fine hairs, the 

 somewhat reduced mastigobranchs. 



The branchial formula appears to be 



Pleurobranchise 0.0.1.1.1.1.1 



ArthrobranchiiB 0.1.0.0.0.0.0 



Podobranchiffi 1.0.0.0.0.0.0 



Mastig'obranchise 1.1.1.1.1.1.0 



but as the specimens are very small and the gills not very 

 well preserved in all cases, too much reliance should not be 

 placed upon it. I examined a great many specimens very 

 carefully, and the above represents the conclusions I came to. 

 After a large number of careful measurements I drew up the 

 following as the average measurements of the adults : — 



6. ?: 



millim. millim. 



Entire length 19 22 



Length of carapace 7 8'5 



Length of firat antennae 7*5 9 



„ second ,, 18 20 



„ first pereiopod 5 5-5 



„ second „ 6-5 7 



third „ 6-25 6-5 



„ fourth „ 6 6-25- 



„ fifth „ .5-5 6 



For other species of the genus Af^a see : — 



(1) Leach.— Trans. Linn, Soc. Lond. vol. xi. 1815, p. 345. 



(2) Randall.—" Crustacea of the Sandwich Islands," Journ. Acad'. 

 Nat. Sci. Philadelphia, viii. pt. i. p. 140(1839). 



(3) Newport.— "Species of Atpa from New Zealand &c.," Ann. & 

 Mag. Nat. Hist. vol. xix. 1847, p. 158. 



(4) De Haan.— Fauna .laponica, Crustacea, 1850, p. 186, pi. 0.. 



(5) Dana.— Crustacea, 1852, vol. i. p. 540. 



