422 



CEYLON PEARL OYSTER REPORT. 



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

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

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



I. Inner sub-orbital spine small var. A. 



II. Inner sub-orbital spine large. 



a. Carapace strongly pilose var. B. 



b. 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 Corystidae 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.l. = 3 - 80 ; Ch.l. (smaller) -j- Ch.l. (larger) 

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

 F.l. (smaller) -j- F.l. (larger) = 075. 



Remarks. The small size of the specimen may he noted Alcock refers to some 



