426 CEYLON PEARL OYSTER REPORT. 



The photograph (fig. 11) should be compared with NOBILI'S figures. It might 

 conceivably be included under var. orientalis, but does not agree well with either. 



Length of large propus is in adult male (a) much less than that given by ALCOCK, 

 who had before him 300 Indian specimens (ALCOCK'S index, large propus 1. H-C.l. = 3 '00). 



Ocypoda ceratophthalma (PALLAS, 1772) A.6, p. 345. 



Localities: Trincomalee, mangrove swamps, two specimens (6, c) ; Galle, one 

 specimen (a). 



Description : (a) ad. ? . (b) ad. ? . (c) ad. . 



C.I ;> . 13-50 30-00 36-50 



C.b.-j-C.l 1'02 1-13 1-07 



Projection of eye stalk beyond eye (lower border) -7- C.I. . O'O * 0*10 0'29 



C.b. is a straight line uniting points of lateral borders where the serrulate line forks. 



In adult female (b) the outer band of granules of the ischium of external maxillipeds 

 is somewhat obsolescent, tending, in conjunction with a specimen of 0. platy arsis in 

 the present coUection, to cast doubt upon granulation of this region as a character of 

 specific value. 



Ocypoda platyarsis, H. M.-Eow., 1852 A.6, p. 348. 



Localities : Gulf of Manaar, one specimen (d) ; Trincomalee, mangrove swamps, 

 three specimens (a, b, c). 



Description : (b) young ? . (c) young ? . (d) adult ^ . 



C.I 15-00 24-00 50-00 



C.b.^C.l .' 1-27 1-34 1-26 



Projection of eye stalk beyond eye (lower bord.)-r-C.l. . 0*10 0'19 



The distinction between this species and 0. ceratophthalma in regard to C.b. -f- C.I. 

 holds, in the present specimens, for both adult and young, lii adult male (d] the 

 granulation of ischium of external maxillipeds approaches the condition recorded above 

 for an adult female specimen of O. ceratophthalma. 



Dotilla myctiroides (H. M.-Eow., 1852) A.6, p. 368. 



Localities : Off Mutwal Island, three specimens ; coral reefs, Gulf of Mauaar, three 

 specimens ; Galle, twenty-three specimens. 



Description: C.I. of an adult male = 8 '50. 



All the specimens are males except a single immature female from " Coral Reefs, 

 Gulf of Manaar." All the males are mature save one, or perhaps two. 



The immature female has seven separate abdominal terga. 



Remarks. Is the striking preponderance of males over females in the collection 

 correlated with a difference in habit, the latter staying at home in the mud ? 



