408 CEYLON PEARL OYSTER REPORT. 



Description: An adult male. The central part of the carapace is smooth, i.e., the 

 pearly tubercles are here absent. 



Epixanthus frontalis (H. M.-Emv., 1834) A.3, p. 185. 



Locality : Trincomalee, two specimens (<i, l>). 



Description: C.l. C.b.-=-C.l. Frontal b.-=-C.l. Frontal b. -f- C.b. 



(a) adult 6 . . . 13'25 1'64 (V57 0"34 



(6) ovigerous ? . . 16-00 1'62 0*56 0-35 



Pilumnus vespertilio (Fabricius), 1793 A.3, p. 192. 



Locality : Trincomalee, one specimen. 



Description: An adult male, C.L = 19*0. The sub-hepatic denticle of the right 

 side is double, and that of the left side is represented by a group of three granules. 



Pilumnus longicornis, Hilgendorf, 1878 A.3, p. 193. 



Locality : Gulf of Manaar, two specimens. 

 Description : -Both adult males. 



Pilumnus cursor, A. M.-Edw., 1873 A.3, p. 195. 



Locality : Gulf of Manaar, one specimen. 



Description: Female, probably adult. C.l. = 8 "00. 



This specimen agrees very fairly with Alcock's description of the samples which 

 he puts with a query under this species. However, an area occupying the distal part 

 of the lower portion of the outer surface of its larger chela (say one-third of whole 

 outer surface) is naked and polished. Its fingers are dark brown. 



Actumnus setifer (de Haan), var. tomentosus (Dana), Miers A3, p. 202. 



Locality : Pearl banks, Gulf of Manaar, four specimens (including a) ; off Mutwal 

 Island, two specimens (6, c) ; south of Modragam, one specimen. 



Description : The series includes six males all perhaps adult and one ovigerous 

 female. C.l. of the latter = 5 - 5. 



In male specimen (a) the denuded carapace appears smooth to the naked eye, but 

 fine granules are revealed by the lens. A similar fine granulation occupies the 

 central part of the carapace of males (b) aud (c), in both of which an antero-lateral 

 strip is granular to the unaided eye. Distinctness of areola? possesses high variability ; 

 specimens (c), (a), and (6), together with a Torres Straits specimen in the British 

 Museum, form a series linking tomentosus and setifer in respect of this character. 



Remarks. The evidence of the British Museum specimens and of those before me 

 compels me to consider, with Miers (" Alert," p. 225), that tomentosus and setifer are 

 a single species. Alcock kept them apart, however, and in so doing he had before 

 him 32 specimens of the former and 53 of the latter. It would be interesting to 

 have some exact knowledge of variability within such considerable samples. 



