44 CHONDROPTEKYGII. BATOIDEI. 



46. (3.) Rbinobatus thouini. 



Raie thouin, Lactptde, H. N. Poiss. i, p. 134, pi. i, figs. 3-5. 

 Rhinobatus thouini, Mull. Sf Henle, Plagios. p. 120; Day, Fish. India, 

 p. 732, pi. cxc, fig. 4 (see synon.). 



Snout of moderate extent, contained 5 or 6 times in the total 

 length ; the width of the interorbital space 2| in the length 

 of the snout. Anterior nasal valves not dilated laterally. The 

 distance between the outer angles of the nostrils equals two thirds 

 of the length of the preoral portion of the snout ; the length of 

 the nostrils is more than twice the extent their bases are apart. 

 Mouth straight. Rostral ridges confluent in almost their entire 

 length. Teeth small, upwards of one hundred rows in either jaw. 

 Fins the two dorsals of about the same size, high and pointed, 

 the first if laid flat nearly reaching the base of the second dorsal ; 

 caudal 6 in the total. Scales skin granulated with a row of 

 compressed spines along the middle of the back and smaller ones 

 over the shoulders and above the eyes. Colour brown, becoming 

 yellowish white beneath. 



Hob. From the Red Sea through the seas of India to the 

 Malay Archipelago. This species attains to 6 feet in length, 

 according to Bleeker. 



47. (4.) Rhinobatus columns. 



Rhinobatus columnae, Bonaparte, Faun. Hal. iii, pi. 152 ; Mull. 8f 

 Henle, Plagios. p. 113; Day, Fish. India, Supplement, 1888, p. 811 

 (see synon.). 



Snout rather elongated, the distance between the outer angles of 

 the nostrils is equal to two fifths of the length of the preoral portion 

 of the snout. Each anterior nasal valve connected to a fold of 

 skin that passes towards the median line and so nearly joins that of 

 the opposite side. The upper rostral ridges are convergent in front. 

 Back finely granular, with a median row of small tubercles. 

 Colour brown ; young examples have a white snout. 

 Hob. Mediterranean, the Indian and Atlantic Oceans. 



Family III. TORPEDINID^E. 



Trunk broad and disk smooth. Anterior nasal valves confluent 

 and forming a quadrangular flap. Body gradually passing into 

 the tail, which latter has a rayed dorsal (except in Temerti) and 

 caudal fin ; a longitudinal fold along both sides. An electric 

 organ situated between the pectoral fin and the head. 



The upper surface of the electric organs in these fishes is positive 

 and the lower negative. 



Geographical Distribution. Tropical, subtropical, and temperate 

 seas. In India the species of this family do not appear to be used 

 as food. 



Synopsis of Indian Genera. 



Two dorsal fins ; spiracles immediately behind the eyes .. 1. NAHCINK. 

 One dorsal fin 2. ASTRAPE. 



