1901.] MOTH ER-Of -PEARL OYSTERS. 391 



processes of M. vidyuris. Ground-colour wliite, with G to 10 

 pjreen, brown, or black radii, which are very variable, in some 

 cases being almost entirely suppressed, in others being confluent, 

 so that the shell is of a uniform dark colour. Interior of the lip 

 white, with black or dark purple blotches, cori'esponding to the 

 radial bands. Nacre lustrous, tinted with brassy yellow, with a 

 steely sheen, transparent, showing the blotchy external markings 

 distinctly through its substance, as depicted in Gould's figure. 



Length of hinge 26 mm. ; total antero-posterior measurement of 

 shell 37 mm., do. of nacre 28 mm., total dors.-venlr. measurement 

 of shell 37 mm., do. nacre only 28 mm. The greatest antero- 

 posterior measurement of shell is in the ventral third. 



Distribution. Conflict Group, British New Guinea, on dead coral- 

 reef flats (//. L. J.). Other localities in New Guinea waters: 

 Moresby Island, Samarai, Bonvouloir Group, SiC. {H. L. J.) ; 

 Badu (MulgraA'e Island), Torres Straits, in rock-pools (//. L. J.). 



"Australia"; Keeling Island: Piji ; Lord Howe Island (./. 

 Brazier, Esq.) ; Samoa {Rev. S. J. Whitmee) ; Loo Choo Isls. 

 {H. Seebohrn, Esq.) : in British Museum. 



? Distinct, S. Africa, Ponsouby coll., B.M. 



Species 27. Margaritifera mauritii, n. sp. (Text-fig. 95.) 



Type B.M. No. 1885.9.19.14. Attached to pumice-stone 



found floating off Mauritius (Robillard). 



Shell oblique, inequivalve, left valve very convex, right valve 



comparatively flat. Posterior luargin very distinctly sinuated, as 



iu M. vulgaris. Lappet-like lip-processes resembling those of 



Text-fig. 95. 



Murgaritijera mauritii, iiiit. size. 



M. pitcairnensis, M. lurida, and M. panasescf, strong and finger-like, 

 without transverse markings. Teeth as in M. vuh/aris. Coloration 

 unusually rich compared with the rather uashy external markings 

 of most species ; very variable, from dark reddish browu to golden 

 yellow and pale grey, with six to eight ^vllite or dark radii of 



26* 



