THE SLUGS OF NATAL. 167 



part (I5 in. from head). Foramen situated about h in. from 

 tip of tail. 



''Colour. — Chestnut-brown, becoming darker towards tail, 

 paler along the keels and on top of the tubercles or granules ; 

 no black markings, the deeper tone of the anastomosing lines 

 and stri« appearing more the effect of shade than of pigment ; 

 no yellow tint on any part ; foot brownish pinky-grey (like a 

 sunburnt liand) . 



" While crawling the angles become less conspicuous and the 

 concavity of the surfaces much shallower than when inactive. 

 When touched with the finger the body becomes more rigid, 

 the keels much accentuated, and the concavity between 

 deeper. 



" The lateral keels, like the dorsal, reach the whole way 

 from head to tail. 



" The two parallel stria3 on the dorsal surface, and the one 

 stria on each of the lateral surfaces, are very distinct, and no 

 similar line is visible on the ventro-lateral surfaces. 



" The keels are not so accentuated in spirit as they are in 

 life while the slug is being handled. 



" There are very few radiating strias from the foramen. 

 Lower pair of bifid tentacles very small, and seldom pro- 

 truded, being quickly withdrawn on contact with the damp 

 blotting-paper on which the slug was crawling. The lower 

 fork of these second tentacles is nearly white, the upper 

 being the same colour as the foot, but with black points, like 

 the eyes in the upper tentacles. 



'' The sluo- leaves a mucous track." 



Apera natalensis Cllye. 



Altera natalensis Collinge, Ann. S. A£r. Mus., 1900, vol. ii, p. 3, 



pi. i, figs. 3, 4. 



Animal limaciform, sub-cylindrical, broad posteriorly, taper- 

 ing anteriorly; dorsally reddish-brown with dark greenish- 

 blue mottling ; sides of body orange-red, or dark orange with 

 greenish-blue mottling, which becomes scarce towards the 



