The Opisthohranchiata of Soutli Africa. 81 



The form as in other IdaHae (fig. 6). The tentacles rather large, 

 lobe-like ; the rhinophores strong, not retractile, situated on the 

 sides of the neck proper. The back with weak median crest, other- 

 wise quite even ; its prominent brim somewhat turned up, disappear- 

 ing behind, and the back passing in the tail. The frontal ])rim 

 carries 4, seldom 6 cirrhi, the lateral 8, but the hindermost always 

 coalescent ; the cirrhi pointed, finger-shaped, of nearly equal size, 

 quite even ; the brim quite even between the digitations. Behind 

 the middle of the back stands the gill, consisting of 12, seldom 11, 

 simple-pinnate, not large leaves, set in a wide arch (fig. 6), the 

 hindermost somewhat smaller; the anal nipple a little behind the 

 median leaf, at its base the renal pore. The sides of the body even. 

 The foot nearly as broad as the back, its brim not narrow ; the tail 

 short. 



The intestines shone grayish through the sides and through 

 the foot. 



The central nervous system seemed to be as in Id. elegans formerly 

 described by me {I.e., pp. 153-156). — The number of lamellae in the 

 club of the rhinophores did not seem to be large. The skin (of the 

 back) scantily provided with spicules, which were looser, hardened 

 and crumbling, yellowish. 



The whitish bulbus pharymjeus small, 2-2-75 mm. long; more 

 than the half of it belongs to the (suctorial) crop, that covers the 

 whole of the bulb proper, is somewhat embedded in its upper wall, 

 not connected with it by a short stalk, but opening in it through a 

 slit. This crop (fig. 7) is of the usual structure. On the bulbus 

 proper the rasp-sheath projects a little behind ; the lip disc is pro- 

 vided with mandibular plates of a breadth up to 0-25 mm., the 

 height of their elements (fig. 8) reaching 0-013 mm. — The tongue 

 rather well developed ; the narrow rasp nearly colourless, with erect 

 tooth-plates (fig. 9). These last colourless ; the height of the lateral 

 plates 0-25, of the outer ones 0-08 mm. The number of rows of 

 plates on the tongue 22-21, in the sheath 10-11, the total number 

 of rows being thus 32-35. The lateral plates (figs. 9, 10a) of the 

 form as in other Idaliae, but the hook finely serrated. The outer 

 plates (fig. 106) also of the ordinary form. 



The sahvary glands (fig. 7aa) whitish, about as long as the bulbus 

 pharyngeus. 



The posterior visceral mass 8 mm. long by a diameter of 4 ; its 

 posterior end rounded, the anterior with long and deep impression 

 on the right and under side by the anterior genital mass. The mass 

 shows only the hinder end of the brownish gray or grayish brown 

 liver naked ; this is elsewhere, on the whole of the upper side, 



6 



