The Opistliohranchiata of South Africa. 103 



the tentacular veil 10 mm. broad ; the breadth of the foot in front 

 (with its angles) 20 mm. ; the length and the breadth of the gill 

 5 mm. — The ground colour of the back black, but the colour reduced 

 by the white longitudinal ribs (in number at the foremost third about 

 25) ; the colour otherwise whitish. 



The foremost lamellse horizontal, the rest obliquely set as usual : 

 on the brim of the back very pronounced cnidocysts. The caudal 

 furrow very pronounced, yellow, 13 mm. long by a breadth of 1'25. 



The hulhus pharyngeus (projecting freely 8 mm.) whitish, 9 mm. 

 long by a height and a breadth of 6. The mandibles yellow, rather 

 strong; the masticatory edge had about 15 series of scarcely 

 prominent roundish quadrangular facets of a diameter up to 

 0'025 mm., belonging to columns of a height up to 0"04. In the 

 yellowish rasp of the tongue 22 series of plates, in the sheath 34, 

 the total number of rows thus being 56 ; the number of plates in 

 the series seemed to rise to 32. The median teeth 0-29 mm. broad, 

 their hook with a little denticle on each side, more outwardly 6-7 

 coarser denticles on each side. The lateral plates quite as above, 

 reaching a height of 0*30 mm. 



This form seems specifically different from the foregoing. Of the 

 hitherto known species of Pleurophyllidiidge only PI. natalensis, 

 cygnea,-'- and Mulleri \ show the margin of the lateral plates (with 

 the exception of the first always finely denticulated) even (not 

 denticulated), but from these species PL. euchroa seems to differ 

 by different character of the masticatory edge of the mandibles. 



4. Pl. microdonta, B, n. sp. 

 PI. VIII., figs. 17-22. 



Off Constable Hill (NNE. 6h miles) one specimen was taken by 

 large trawl from a depth of 33 fms. and green mud bottom. It 

 was in a very bad state of preservation, very hardened, somewhat 

 contracted and bent. 



The length seemed to have been 3 cm. by a breadth of 1*5 and 

 a height of 1. The ground colour of the back seemed to have been 

 black, the whitish lines as usual. 



A caruncle before the rhinophores could not be detected. The 

 gill, the lateral lamellae, and the cnidocysts as usual. 



The length of the bulbus ■pharyngeus 4 mm. by a breadth of 3'5 



* R. Bergh, " Neue Beitr. zur Kenntn. d. Pleurophyllidien. " Malacozool. 

 BL, xxiii., 1876, pp. 9-13; taf. 1, figs. 1-7. 



t H. V. Jhering, " Zur Kenntniss d. Nudibranchien der brasilianischen kiiste." 

 Malakol. Jahrb., xiii., 1883, pp. 223 228; taf. 9, fig. 1. 



