2 0. TATE REaAN. 



above the extremity of the inner edge of the pectorah Caudal 

 feebly heterocercal, with uppei' lobe well developed. 



Tavo specimens, each about 750 mm. in total length, the one 

 from the coast of Natal, taken at a depth of forty fathoms, the 

 other from False Bay, Cape of Grood Hope, received in 1899 

 from Dr. J. D. F. Gilchrist. 



The presence of six gill-clefts in a Pristiophorid is a most 

 unexpected feature. As has been ])ointed out by Jaekel, the 

 Pristiophoridas are closely allied to the Squalidas (Spinacida?), 

 a family in which the gill-clefts are constantly five in number. 

 The anatomy of the fish described above is extremely similar to 

 that of Pristiophorus cirratus and there is no evidence 

 of relationship to the Notidanoids. It may be that the large 

 number of gill-clefts is a iirimitive feature retained in this 

 fish and lost in its allies,^ in which case it would follow that 

 the reduction in number to five has been independently 

 arrived at in different groups. On the other hand, there is 

 the possibility that an increased number of gill-clefts may 

 sometimes be a feature of specialisation, just as in the case 

 of certain groups of Teleosts with an increased number of 

 vertebrae or of pectoral pterygials, which are now regarded 

 as derived from forms with a lower number. 



Raia ocellifera sp. n. (PI. II). 



Snout with a short, obtuse, triangular projection. Diameter 

 of eve 3A-3I- in the lene-th of snout and 1|— li in the inter- 

 orbital width. Distance between outer edges of nostrils 

 greater than their distance from the tip of the snout. Teeth 

 obtuse, in 48-50 series in the upper jaw. Anterior border of 

 pectoral undulated. Body smooth, except for some small 

 asperities along the anterior margin of each pectoral. Three 



^ This view is sui^portedby the presence in Raia of a structm-e which 

 lias l^een interpreted as tlie remnant of a sixth gill-cleft, and hy the 

 recent discovery of a sixth branchial arch in the embryonic C estracion 

 (Mrs. Hawkes, ' Journ. Anat. and Phys.." xi. 19o5. pp. 81-84). 



