4 Transactions of the South African Philosophical Society. 



The yellow hermaphrodite gland covering the end and the hinder 

 upper side of the liver with a layer 4 mm. thick, 8 mm. long, and 

 7 mm. broad, its duct long and strong. The yellowish white and 

 grayish anterior genital mass as usual, the grayish globular spermato- 

 theca 6 mm. in diameter. The brownish gray penis 11 mm. long 

 by a diameter of 2*25, nearly cylindrical, the inside of the praeputium 

 with strong blackish longitudinal folds ; the white glans 7 mm. long,, 

 very pointed, somewhat turned, with rather deep furrow. 



2. Apl. allochroa, B. n. sp. 

 PI. I., figs. 4-10. 



Two individuals of nearly the same size were caught at Knysna at 

 low tide on the shore between the jetty and the village. One of them 

 gave off a good deal of red pigment. 



The length was 25 mm. with a breadth of 10 and a height of 11, 

 the oval mantle 12 mm. long, its round hole of a diameter of 8, the 

 sipho 4 mm. long by a breadth of 3, the length of the somewhat 

 flattened gill 5 with a breadth of 2 mm. ; the foot 4 mm. broad, the 

 wings 13 mm. long, their height (on the inside) 5, the length of the 

 tail 4. They were one-coloured, yellow, merely the cleft of the 

 rhinophores and the tentacles black and on the free inner margin 

 of the foot-wings a series of small black spots, the gill slightly 

 brownish. 



The skin quite smooth all over. The foot-wings coalescent 

 behind. The under-side of the mantle brim brown, richly provided 

 with small glands. The shell (fig. 4) very difficult to see and to 

 loosen, 11 mm. long with a diameter of 9, very flattened, very thin 

 cuticular, with small nucleus, without any trace of calcification, 

 nearly colourless. 



The central nervous system as usual. 



The bidbus phwryngeus dirty yellowish, 5 mm. long with a breadth 

 of 3*5 and a height of 3 ; two grayish, as it were, palate plates shone 

 through the roof of the mouth cavity, but no trace of armature could 

 be detected. The longish triangular mandibles brown, anteriorly 

 nearly black, 1*75 mm. high by a breadth up to 1, their elements 

 (fig. 5) up to 0*18 mm. in height by a diameter of 0*009. The rasp 

 of the tongue yellowish brown, containing 22 rows of plates, in 

 addition 15 in the sheath, the total number of the series thus being 

 37 ; about 20 plates in the rows. These last with exception of the 

 2-3 outer brownish yellow ; the length of the 6 outer (fig. 8) was 

 0-0G-0-08-0-1-0-12-0-18-0-25, and seemed not to become higher, 

 the breadth of the median plates 035 mm. These last (fig. 6) with 



