214 HUGH WATSON. 



of Mai.. 1902, vol. ix, pi. vi, fig. 6G ; Simroth, Bronn's Klass. u. Ordii. 

 d. Tier-Reicbs III, Gastr. Piilm., 1909, pi. iv, fig. 11 ; Collinge, Ami. 

 Natal Mus., 1910, vol. ii, p. 166; Simrotli, Bronn's Klass. n. Ordn. 

 d. Tier-Reichs III, Gastr. Pulni., 1912, p. 611; Connolly, Ann. 

 S. Afr. Mus., 1912, vol. xi, p. 62. 



External Characters (PI. VII, figs. 12, 13; and 'Ann. S. 

 Afr. Mas.,' vol. ii, pi. i, figs. 5 and 6). — Animal rather slender, 

 approximately hexagonal in section, owing to the presence of 

 four prominent longitudinal keels, two on each side of the body. 

 Upper keels separated by about three-fifths of the breadth 

 of the slug, and nearly parallel to each other, excepting pos- 

 teriorly, where they diverge very slightly just in front of the 

 respiratory opening, and then gradually converge behind it, 

 until they unite to form a single median keel, 3 or 4 mm. in 

 length, at the hind end of the animal. Lower keels extend- 

 ing along the whole length of the slug, about half way 

 between the upper keels and the edges of the foot, but sloping 

 downwards towards the hind end. The areas between the 

 keels are nearly flat when the animal is in motion, but when 

 it contracts they become deeply concave. Body, as seen 

 from above, tapering to an acute angle posteriorly, but when 

 viewed from the side the hind end appears blunter owing to 

 the short median keel (though not always so rounded as in 

 fig. 13). Outer lip of respiratory opening narrow, exposing 

 the inner lip, Rug^e minutely subdivided. Dorsal grooves 

 well marked, usually about 1 mm. apart, separated by a row 

 of rugfe which is single in front and behind but often 

 becomes irregularly double towards the middle, converging 

 slightly as they approach the respiratory opening, but not 

 uniting with each other. Lateral grooves also conspicuous, 

 extending along each side of the body as far as the head 

 about half way between the upper and lower keels, the right 

 one ending in the genital opening. Sub-lateral grooves few 

 and irregular, only two or three being traceable on each hide. 

 Radial grooves well marked, forming slight notches in the 

 keels where they cross them. Both radial and sub-lateral 

 grooves terminate below in a longitudinal groove, parallel to 



