422 



CEYLON PEARL OYSTER REPORT. 



(Crust, in 'Fauna Japonica,' p. 44, pi. ii., fig. 5, 1835); (3) the ovigerous female 

 ((/, C.I. = 23) goes with the " Challenger" specimens preserved in the British Museum. 

 Some variable characters of the species may he set forth in the form of a key. 



I. Inner sub-orbital spine small . . . . V : . '.''.'-.'',.' . . var. A. 

 II. Inner sub-orbital spine large. 



a. Carapace strongly pilose . .. . . . . var. B. 



I). Hairs on carapace few or absent. 



i. Spiniform outer angle of orbit as well developed as first 



antero-lateral spine . . ': . . . ...".' . . var. C. 



ii. Spiniform outer angle of orbit much shorter than the 



first antero-lateral spine '.'.'.! . . var. I). 



The family Corystidse is new to the Ceylon fauna. 



CATOMETOPA. 

 Catoptrus nitidus, A. M.-EDW., 1870 A. 6, p. 307. 



Locality : West of Periya Paar, 17 to 24 fathoms. 



Description : Male, apparently adult, C.I. = 3'80 ; Ch.l. (smaller) -r-Ch.l. (larger) 

 = 0-92; C.b.-KU. = 1-51 ; F.I. (larger) -=- C.I. = 1 "05 ; Ch.l. (larger) -r C.I. = '33 ; 

 F.I. (smaller) -7- F.L (larger) = 075. 



Remarks. The small size of the specimen may be noted ALCOCK refers to some 



