100 Marine Investigations in South Africa. Vol. V. 



length of the back about 30. The lamellae on the under side of 

 the brim of the back numerous, especially at the thin and narrow 

 margin ; the larger ones, in number about 30, descending obliquely 

 from the narrow margin forwards ; the margin proper of the back 

 showed no openings of cnidophore sacs. The sides low ; the 

 genital and renal opening as usual, as also the rather prominent 

 anal papilla. The margins of the rather strong caudal furrow 

 prominent. 



The whitish hulhus 'p^Mryngeus 12 mm. long by a breadth and a 

 height of 11. The yellowish mandibles united 10 mm. long and broad, 

 the height of the convexity 4 mm. ; their inner half much thicker 

 than the outer ; the mandibular process as also the whole of the 

 masticatory edge straight and quite even. The rasp of the tongue 

 yellow, containing about 25 series of teeth, in the sheath moreover 

 about 33 series, the total number being thus 58. In the lateral series 

 about 50 plates. The plates were yellow and yellowish ; the breadth 

 of the median plates 0"30 mm., the height of the first lateral 0"08, of 

 the fifth 0"28, and this height was scarcely surpassed. The median 

 plates broad (fig. 23), with short hook and on each side about 10 

 denticles ; the lateral plates also of usual form, mostly with 4-6 very 

 small denticles (fig. 24), the outermost mostly without these. 



The upper salivary glands (gl. salivales) as usual ; the under 

 (gl. ptyalinae) very strong. 



The oesophagus and the stomach as usual; the intestine 3 cm. 

 long by a diameter of 2-2-5 mm., in the rectum some dark animal 

 matter. The liver ramifications in the lateral laminge as usual. No 

 cnidocysts could be found ; but in the narrow margin of the back 

 fine gland-openings. 



The large hermaphrodite gland dirty brown, 18 mm. long by a 

 breadth of 12 and a height of 10 ; the ampulla of the hermaphrodite 

 duct brown. The large anterior genital mass white and whitish, 

 15 mm. long by a height of 8 and a breadth of 7 mm. ; the seminal 

 vesicle large. 



This species seems different from others known from the coast 

 of Africa, from the PI. natalensis, B., PI. Pctersi, B., and perhaps 

 from the PL Horatii of Eliot.* The mandibles have a straight, 

 even masticatory edge, the lateral plates of the rasp have mostly 



* Eliot, " On some Nudibranchs from East Africa and Zanzibar," ii. 

 Proc. Zool. Soc. of London, 1903, i., pp. 251-252. 



The description of this species (given by Crossland) is not at all clear ; the 

 assertion of Eliot that the gill is wanting is very doubtful ; the median plates 

 have a long cusp, and the cnidocysts are distinct. 



