The Opisthobranchiata of South Africa. 87 



Bulbus pharyngeus ut in Tritoniis, ita mandibulse cum processu 

 masticatorio, et ita radula. 



This genus * differs from the other generic types chiefly in the 

 total icant of branchice on the sides of the back. Otherwise the 

 group agrees almost entirely with the other Tritoniee in the form of 

 the body, the frontal veil with its peculiar tentacles, and the sword- 

 knot-rhinophores. It has, too, the same form of the bulbus 

 pharyngeus with its mandibles and of the armature of the tongue. 



Tritonidoxa capensis, B. n. sp. 

 PL VIII., figs. 8-13. 



One specimen of this form was taken by dredge off Glendower 

 Beacon from a depth of 66 fms. ; the bottom was broken shells and 

 stones. 



It was 3-2 cm. long by a breadth of 1-5 and a height up to 1 cm. ; 

 the breadth of the frontal (tentacular) veil was 11 mm., the height of 

 the rhinophores 6, the breadth' of the brim of the back 6 mm. ; the 

 breadth of the foot 11 mm., of its brim 3. It was of a uniform white 

 colour. 



The form of the animal, as in other Tritoniidae, somewhat pointed 

 towards the hinder end. The frontal veil (fig. 8) not much projecting, 

 quite even, at the margin with 2-3 short finger-shaped processes on 

 each side besides the tentacular. The margin of the rhinophore 

 cavities somewhat prominent, even ; the stalk of the rhinophores as 

 high as the swordknot-like club. The back entirely even, its brim 

 rather broad, very undulating, also quite even on the under side. The 

 sides of the body rather low ; from the genital opening the glans of the 

 penis projected (very curved) for a length of 2*5 cm. ; the small anal 

 papilla at the base of the brim of the back behind the middle of the 

 length of the body. The foot rounded in front, with a slight marginal 

 furrow; the brim not narrow. On the left side an intestine shone 

 grayish through. 



The cavity of the body ending 14 mm. from its end. 



The central nervous system as in other Tritoniidae, the cerebro- 

 pleural ganglia not quite as large as the pedal. 



The white bulbus pharyngeus of typical form, 8 mm. long by 

 a breadth of 6 and a height of 5 mm. ; the muscular plate on the 

 fore side of the mandibles was as usual. The mandibles measured 

 in a straight line 6 mm. ; they were yellowish, only the masticatory 

 edge being brownish yellow ; their form was as usual, but rather 



* Ao4'a, presumption, conjecture. 



