THE CAIiNIVOROUS SLUGS OF SOUTH AFRICA. 197 



by their external charactei's, excepting in the case of one form, 

 of which only a single specimen has been collected. 



Apera gibbonsi rubella n. suhsp. 



External Chaeactbks (PI. VII, figs. 3, 4, 5 ; PI. VIII, figs. 

 16, 17). — Animal broader than the typical form of Apei-a 

 gibbonsi, tapering more abruptly at the hind end. Back 

 usually slightly flattened just behind the respiratory opening. 

 Reticulation of skin very similar to that of the typical form 

 of A. gibbonsi, but not so coarse, the grooves being more 

 numerous and less deep. Dorsal grooves usually less than 

 1 mm. apart, and united for about 4 mm. in front of the 

 respiratory opening. 



Body thickly mottled with dark grey (which sometimes 

 has a bluish tinge in specimens preserved in spirit). The 

 small patches of colour are usually ill-defined, and tend ta 

 coalesce dorsally, where they are most abundant; but a 

 narrow paler band, more sparsely mottled, is generally left 

 along the centre of the back from the head to the respiratory 

 opening. Laterally the dark pigment is chiefly concentrated 

 on the sides of the grooves in the skin, but it dies out completely 

 a short distance above the peripodial groove. The ground- 

 colour of specimens preserved in spirit is whitish, tinged with 

 dull red dorsally, but living examples ai-e deeply coloured with 

 an unstable orange-red pigment, so that the animal is usually 

 reddish-brown above, merging into deep reddish orange on 

 the sides, while the foot- sole is of a paler orange colour. 



The following are the approximate dimensions (in alcohol) 

 of the smallest specimen with fully developed reproductive 

 organs, and of the largest specimen, which I have examined. 



Length ..... 



Breadth in middle . 



Breadth at respiratory opening- 

 Breadth of foot-sole 



Greatest height 



Distance from respiratory open- 

 ing- to hind end . .10 ,, .13 



