360 CEYLON PEARL OYSTER REPORT. 



Ebalia diadumena, ALCOCK, 1896 A. 2, p. 187. 

 Locality : Galle, two specimens. 



Description : (a) young ? . (/>) 3 . 



0.1 475 6-50 



C.H -5-0.1. 1-05 0-96 



Ch.l. -=- C.I. . . . (a) 1-37 (ft) 2 -00 

 F.L-rH.1. . : . 0-83 077 

 H.b. -r-H.l. . 0-83 0-69 



This is first record of male. It differs from ALCOCK'S female (Palk Straits) in a few 

 respects : (I) the gastro-cardiac groove is hardly to be distinguished ; (2) the cheliped 

 granulation is not so extensive ; (3) about middle of striation on upper surface of 

 immobile finger is a prominent elongated laterally compressed granule ; (4) abdominal 

 tergum VI. is armed with strong terminal tooth. 



Ebalia maldivensis, BORRADAILE, 1903 B.VL, p. 437, fig. 116. 



Locality : Gulf of Manaar, one specimen. 



Description. : Ovigerous female, 0.1. = 575 ; C.b. -5-0.1. = 1 '13 ; Ch.l. -s-C.l. = 1 '22 ; 

 F.I. -5-H.l. = 075. The mounds on dorsum of carapace are all distinct. 



Myra* fugax (FABRICTUS), 1798 A. 2, p. 202. 



Locality : Aripu coral reefs, Gulf of Manaar, three specimens (/>, d, /*) ; Trin- 

 comalee, five specimens (a, c, v, g, h) ; Galle, three specimens (j, k, I) ; off Manaar 

 Island, one specimen (i). 



Description : a-h, young. ovig. ad. ad. ad. 



&(?).<*(?). (?). /(?). /*(?). (?). /(?). (<?). <;(<?). g(J). /(<?). *(<?) 



C.I 9'00 12-00 12-25 12'50 17 '00 IS'OO 26'00 | 875 11*50 16'50 19*00 2475 



C.b. -j- 0.1. . 0-86 0-87 0-88 0'86 0'88 0'86 0'85 0*89 0'87 0'82 0'87 0'86 

 Ch.l. -5-0.1. . 1-69 179 179 176 1-98 1'86 2-12'l'83 1'85 1'95 2'33 2'38 

 H.l. -5-0.1. . 0-39 0-44 0-47 0'42 0'51 0'47 0'58 0'46 0'46 0'51 0'62 0'65 

 F.I. -T- H.I. . 0-93 0-86 078 0'90 0'80 079 077 , 0'81 0'86 0'68 074 072 

 H.l. -5-H.b. . 2-29 2-50 2'87 2'50 2'69 2'67 3'16 2'09 2'62 2'83 3'36 3'56 



Oh.l. is the sum of lengths of its segments, measured along median line of posterior 

 surface. C.I. is without the spine. 



Among the adult specimens considered to be mature, the sexual dimorphism in 

 regard to cheliped length is by no means so marked as ALCOCK records. 



In one specimen the more acutely bidentate and upturned front is somewhat 

 reminiscent of M. brevimana. It lias also a well-marked median longitudinal carina. 



Specimen (i), an ovigerous female, is an interesting form which deserves note. It 

 tends to combine characters of M. fugax, M. affinis, and M. brevimana. In slender 

 build of chelipeds and in index F.I. -5- H.l. it resembles M. fugax. In indices Ch.l. -5-0.1. 

 and H.l. -5- 0.1. it more nearly approaches M. vffinis and M. brevimana. The prominence 



* Miss RATHBUN unites this genus with the older genus Perseph-ona, LEACH, 1817, 



