The O-pisthohranchiata of South Africa. 101 



some few denticles, the nuchal region is even (and the margin of the 

 back without cnidocysts). 



2. Pl. Gilchristi, B. n. sp. 

 PI. VIII., figs. 14-18. 



Of this form one individual was procured off Sebastian Bluff 

 (July 11, 1900) from a depth of 40 fms. by shrimp-trawl, two off 

 Cape St. Blaize from muddy bottom and a depth of 35 fms. by large 

 trawl, and one more off Cape Point Lighthouse. 



The three last had a length of 20 and 27 mm. The first, which 

 was thoroughly examined, was 24 mm. long by a breadth of 15 and 

 a height of 8 mm., the tentacular shield 9 mm. broad ; the brim of 

 the back mostly 4-5 mm. broad, the length of the gill 4-5; the breadth 

 of the foot 12, the length of the (not very pronounced) furrow of the 

 tail 4 mm. — The ground colour of the back grayish, more blackish in 

 front, the folds whitish, otherwise the animal seemed to be uniformly 

 white. 



The lateral lamellas as above, in number about 40, about half of 

 which were larger ; no cnidal pores or bags were seen. The neck 

 without caruncle, folds, or papillae. 



The anal papilla formed a prominence 5 mm. in height. 



The central nervous system as usual. The otocysts 0'06 mm. in 

 diameter. 



The biilbus pliaryngeus 3"5-4 mm. long by a breadth and a height 

 of 2-5. The mandibles of a length of 3 mm. by a breadth of 2-8, 

 their masticatory edge yellow, elsewhere nearly colourless ; the 

 masticatory margin (fig. 14) with (about 10) series of very small 

 blunt cones of a height of about 0-025 mm. (in two individuals). 

 The very bright yellowish rasp of the tongue contained, in the 

 two individuals examined, 22 and 25 series of plates, in the sheath 

 moreover were counted 23 and 21, the total number of series being 

 thus 45-46. In the lateral series (of three individuals) 41, 33, and 35 

 plates. The plates rather pale ; the breadth of the median 0-17- 

 0"18 mm., the height of the first lateral 0'12, of the next 0-16, 

 rising to 0*18, that of the outermost about 0*10 mm. The median 

 plates had 4 stro7ig denticles on each side (fig. 15), the first lateral 

 with (fig. 16) 6-8 not quite small denticles, the plates of about the 

 inner third or eighth part of the rasp provided with a few very 

 fine denticles (fig. 16), the rest without denticle (fig. 17). 



This form is different from the preceding and does not seem to 

 agree with any one of the hitherto known species. 



