4 Marine Investigations in South Africa. Vol. V. 



The yellow hermaphrodite gland covering the end and the hinder 

 upper side of the liver v^ith 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 jjewts 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 hnlhus pliaryngeus 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 ti-ace of armature could 

 be detected. The longish triangular mandibles brown, anteriorly 

 nearly black, 175 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 

 0-06-0-08-0-1-0-12-018-0-25, and seemed not to become higher, 

 the breadth of the median plates 0"35 mm. These last (fig. 6) with 



