196 HUGH WATSON. 



glands united above crop. Liver of two appi-oximately equal 

 divisions, the intestine only traversino- the right. 



Vascular System. — Pulmonary veins greatly branched. 

 " Posterior aorta " supplying left division of liver and her- 

 maphrodite gland ; two arteries of right division of liver 

 arising from anterior aorta as a single vessel ; anterior aorta 

 passing to right of intestine in typical form; anterior branches 

 of buccal artery separate throughout. 



Reproductive System (PI. XXIII, tig. 143). — Her- 

 maphrodite gland with rather large follicles; common duct 

 rather short, curving twice to the right and twice to the left; 

 vagina narrow ; receptaculuin seminis rather large; recepta- 

 cular duct of moderate length and slender throughout. A^as 

 deferens rather thick excepting near the vestibule, somewhat 

 swollen near the posterior half of the penis to form an 

 epiphallus ; penis short and curved posteriorly in specimens 

 from Zululand ; penial retractor short. 



Habitat. — Typical form : Umgeni valley, Natal (under 

 a stone in a wood ; Gibbons) ; Pietermaritzburg (?, Burnup, 

 Ponsonby) ; Hlabisa, Zululand (Burnup). 



Type. — The type is in the Academy of Natural Sciences, 

 Philadelphia. Other specimens will be found in the Natal 

 Museum, Pietermaritzburg. 



Affinities, etc. — This species is the type of the genus. It 

 differs from all the other species in its radula, buccal retrac- 

 tors, receptacular duct, etc. At the same time it shows a 

 remarkable diversity in some of its organs, specimens found 

 in different localities, and even, in one case, in the same 

 locality, constituting races which differ markedly from each 

 other in their radulte and in a few other important characters. 

 Indeed, it is not at all improbable that these forms will prove 

 to be distinct species. For the present, however, until further 

 specimens liave been collected, I have thought it better to 

 treat them provisionally as subspecies of A per a gibbon si; 

 for although their differences are undoubtedly of considerable 

 importance, in most of their anatomical features they appear 

 to be identical, and it is impossible to distinguish them merely 



