222 ANNALS OF SCOTTISH NATURAL HISTORY 



species, and I include the fish, therefore, as here given, on 

 Mr. Couch's authority." 



Is it any wonder, then, after such over- naming has 

 occurred, that error should have crept in ? But it does seem 

 strange that those who have written more recently on the 

 Rays should have fallen into error. 



As will be seen from the above, Day puts the Cuckoo 

 Ray, and Sandy Ray of Couch as the same species. This 

 he was certainly not warranted in doing, for the follow- 

 ing reasons. First, R. radula is an abyssal form, while R. 

 circularis is not. Second, radula attains a much larger size 

 than circularise and before radula is mature it is longer and 

 broader than mature circularis. What I mean by mature is, 

 that in radula the claspers of the male are not developed 

 beyond two inches long when the fish itself has attained a 

 size considerably beyond circularis, in which these organs 

 are of full size, and the fish producing young. In confirmation 

 of this I have taken many eggs from circularis, and have 

 had them hatched out. Third, in radula the male is always 

 much smaller than the female, while in circularis the sexes 

 are of the same size. Fourth, the claspers in radula differ 

 in form from those of circularis, the former having a sharp 

 spine on the edge which the latter never has. Fifth, the 

 teeth of both species, though similar in form, are not 

 identical. Sixth, the form of the two fishes is very 

 different, the anterior edges of radula being very much 

 straighter than those of circularis, i.e. the anterior edges of 

 circularis are more hollowed out, and the head is more 

 marked off from the body than in radula (see Plate IV.). 

 Seventh, the colour and marking in the two species are 

 different. In radula the ground-colour of the dorsal surface 

 is of a light cinnamon brown, with regularly-placed whitish 

 spots upon it ; while circularis is usually of a yellowish 

 colour, with only the central circular mark on each " wing." 

 In addition to this, it has sometimes white markings similar 

 to those on radnla, and it is from this fact, perhaps, that 

 some ichthyologists believe it to be merely the young of 

 radula, and that the large circular spots disappear with age. 

 This, however, seems to me untenable, for it is mature, and 

 produces its kind while the large marks are still upon it. 



