içog.] N. Annandale : Report on the Batoidei. 39 



In general form and structure all the species of the genus are very much alike. 

 In the Indian species at any rate the structure of the mouth and teeth differs little. 

 The mouth is nearly straight and bears no processes on its floor or cutaneous flap on 

 its roof. The teeth have been briefly described by several authors ; Günther {Cat. Fishes, 

 viii, p. 486) says that they are " very small, uni- or tricuspid "; Müller and Henle 

 describe them as '' mit i — 3 Spitzen " {Syst. Beseht, d. Plagiostomen , p. 168) ; Jordan 

 and Bverman {Fishes of North America, i, p. 86) do not mention them in their account 

 of the North American species. They are so small in the Indian forms that it is im- 

 possible to examine them properly without dissecting them out and mounting them 

 for microscopic investigation. The figure reproduced on page 38 gives an outline of 

 teeth of P. micrura, P. zonura and P. tentaculata . In the two latter species teeth with 

 one cusp are mingled indiscriminately with teeth bearing two cusps ; but apparently in 

 P. micrura all the teeth have one cusp. In the two former species the unicuspid 

 teeth are much more numerous than the bicuspid ones. 



I have not detected any rudimentary denticles in the skin of the Indian forms. 



The species of Pteroplatea are eaten by some castes of Hindus but rejected by 

 others and by Mahommedans as being ' ' fish without fins.' ' 



Pteroplatea micrura (Bloch and Schneider). 



Size moderate (adult females 74 — 82 cm. across disk, males (?) smaller, young 16 cm.). 



Disk as a rule rather less than twice as broad as long, with the pectoral angles sub- 

 acute in the adult, distinctly rounded in the young. The snout hardly projects 

 at all, the anterior margin of the disk forming a very obtuse angle. The distance 

 between the eyes considerably greater than the length of the snout measured 

 from them. The nasal flap distinctly emarginate, delicately fringed. 



Tail variable in length, sometimes longer than disk, as a rule shorter, but always 

 more than half as long, without dorsal fin or cutaneous folds ; serrated spine 

 usually present in the adult but absent or concealed in the young. 



Colour. — The dorsal surface of the new-born yoimg is of a pale greenish grey pro- 

 fusely covered with small, round, blackish spots and with more sparsely scattered 

 and larger white ones. The ventral surface and the tail are white, but there is a row 

 of relatively large, longitudinally oval, blackish spots on the dorsal surface of the 

 latter. Soon after birth the spots disappear from the body, while those on the tail 

 coalesce in pairs and grow round the greater part of the circumference of the tail. 

 A white spot is, however, left in the middle of each of the double black ones on the 

 tail. As the fish grows older the tint of the dorsal surface darkens to deep slate-colour 

 or brownish grey, the spots on the back having completely disappeared before this 

 happens although those on the tail become more distinct and more extensive with age. 

 This species is more commonly captured by the methods employed by Indian 



fishermen than its two congeners, because it is mainly a littoral form. Large numbers 



of small individuals were taken at Puri in January and February practically on the beach. 

 Day states, on the authority of Jerdon, that P. micrura grows to 6 feet across the 



disk {Fishes of India, n, p. 741) ; but in the large series of specimens taken by the 



