90 CEYLON PEARL OYSTER REPORT. 



Tribe : SCYLLAPJDEA. 



Family: SCYLLARLD.E. 



Scyllarus, Fabricitjs, 1793 

 (= Arctus, Dana, 1852). 



Scyllarus tuberculatus (Sp. Bate). 



Arctus tuberculatus, Sp. Bate, ' " Challenger" Macrura,' p. 70, 1888. 



Localities : Pearl banks, Gulf of Manaar (Station III.), 1 specimen, female ; Galle 

 (Station XXXV.), 3 females and 1 male ; Aripu Reef (Station LXIV.), 1 specimen. 



Characterised by large tuberculations on the mid-dorsal line of the carapace and of 

 the first 3 pairs of abdominal segments. Those of the second abdominal segment are 

 very distinctive of the species. 



In this genus all the legs of the male end in a simple dactylos, and in the female 

 there is a poor developed chela on each of the 5 th legs. The propodite digit is not 

 very well developed. 



General distribution : Australia and Ceylon. 



Scyllarus sordidus (Stimpson). 



Arctus sordidus, Stimpson, ' Proc. Acad. Nat. Sci., Phil.,' p. 8, 1860. 



Locality : Coral reef, Gulf of Manaar (Station LIV.), 3 females and 1 male. 

 General distribution : Pacific and Ceylon. 



Tribe: THALASSINIDEA. 



Family : CALLIANASSIDiE. 



Callianassa, Leach, 1813. 



Callianassa rotundicaudata, Stebbing. 



Callianassa rotundicaudata, Stebbing, 'Marine Invest, of S. Africa.' Crust., ii., p. 41, 1903. 



Locality: Cheval Paar (Station XLVIIL), 1 specimen, 18 millims. long. 

 General distribution : South Africa, Ceylon. 



Callianassa maldivensis, Borradaile. 



Callianassa maldivensis, Borradaile, 'Fauna of Maid, and Lace.,' vol. ii., part 3, p. 753. 



Locality: Gulf of Manaar (Station III.), 1 specimen, 24 millims. long. 

 This specimen is imperfect, but it agrees closely with the above species. 

 General distribution : Maldives and Ceylon. 



