1909.] 



R. E. Lloyd : Deep-Sea Fish caught by the " Investigator.' 



143 



One small male specimen^ measuring 36 cm. in its greatest length and 23 cm. in 

 its greatest breadth, was taken from 130 fathoms in the Gulf of Aden. Station 360. 

 Registered No. ^^f ^. 



There are now six species of the genus Raia in the collection, each of which is 

 represented by a single specimen Four of these are from depths of over 200 fathoms. 

 Two are from more shallow water. Of these two R. powelli is from 67 fathoms in the 

 Gulf of Martaban, the other, R. philipi, is from 130 fathoms in the Gulf of Aden. 

 These two resemble one another more closely than any of the others. There is in the 

 Indian Museum another specimen of the genus which was brought ashore by fisher- 

 men at Travancore from water which must have been less than 10 fathoms in depth. 

 This specimen closely resembles R. powelli ' but in some ways it also resembles 

 R. philipi. It is possible that the three specimens are in a wide sense of one species 

 which occurs rarely in the shallow waters around India and shows local variation. 

 The specimens from Martaban and Travancore are both females, while the specimen 

 from Aden is a male. It has been suggested to me that the differences exhibited may 

 be of a sexual nature At present it does not seem advisable to describe the speci- 

 men from Travancore as a new species, nor is it safe to infer without evidence that 

 R. philipi is the male form of R. powelli. The measurements of the three specimens 

 will be given in detail : — 



Name of specimen 



Raia powelli. 



Raia, sp. 



Raia philipi. 



Ivocality 



G. of Martaban. 



Trivandrum. 



G. of Aden. 



Depth 



67 fathoms. 



10 fathoms ( ?). 



130 fathoms. 



Sex 



Female. 



Female. 



Male. 



Total length 



318 mm. 



475 mm. 



350 mm. 



Breadth 



191 ,, 



315 >. 



220 ,, 



Snout to pelvic fin 



187 „ 



290 ,, 



220 ,, 



Vent to snout . . 



150. ,, 



235 .> 



174 >. 



Width of mouth 



26 „ 



46 „ 



32 ,, 



Corner of mouth to front end of nostril 



17 >' 



25 >. 



16 „ 



Length of snout from centre of upper jaw 



54 .> 



78 „ 



60 ,, 



Greatest diameter of eye . . 



9 .. 



12 ,, 



II ,, 



Spiracle 



9 >, 



17 ', 



II ,, 



Interorbital distance 



13 > = 



22 ,, 



16 ,, 



Position of greatest breadth— -^ 









A, from snout 



93 „ 



147 >. 



135 >. 



B , from end of pelvic fin 



94 ., 



143 =, 



85 „ 



Number of teeth- 









Upper j aw 



55 >, 



75 „ 



80 „ 



Lower jaw 



55 -> 



75 .> 



60 „ 



Reg. No 



235 



2708 



1383 





I 



I 



I 



As regards the form of the disk R. powelli and the Travancore specimen resemble 

 one another exactly, and differ widely from R. philipi, in which the greatest breadth 

 is much further back. As regards the shape of the mouth the Travancore specimen 

 is intermediate between the other two (text-fig. i), while as regards the relative 



See Annandale, Mem. Ind. Mus., vol. ii, No. i, p. 16. 



