92 Annals of the South African Museum. 



animal the edges of the orifice are on a level with the ventral surface, 

 but in spirit specimens they are generally more or less raised to form 

 a prominent eminence, bearing the orifice at its summit and papillae 

 on its sides. 



When Opisthopatus w^as first described there v^ere no males and 

 only tw^o indifferently preserved female specimens at my disposal, 

 and the apparently purely transverse sexual orifice seemed to be 

 strikingly different from that of the females of Peripatopsis and 

 other genera, so far as the form of the opening could be ascertained 

 from the literature on the subject. A subsequent careful examina- 

 tion of a number of specimens of various species has convinced me 

 that, after all, these differences are of quite minor importance, as the 

 cruciform orifice is common to several genera. 



Peripatoicles. — In a number of females of Peripatoides leuckarti 

 var. orientalis (Fletcher), which were collected in New South "Wales 

 and beautifully preserved (evidently by drowning) by Mr. Th. Steel, 

 the genital orifice was very distinctly cruciform, the shape being 

 produced by a longitudinal and a transverse slit cutting one another 

 at right angles. In at least one specimen, however, the anterior 

 arm of the longitudinal slit was quite obsolete, the opening being 

 then T-shaped.* The lips of the slits are, like those of a pre- 

 served Opisthopatus 5 , more or less raised to form an eminence, 

 bearing the orifice at its summit and a number of ordinary papillae 

 on its surface, but no spinous pads are present. The orifice, there- 

 fore, differs from that of the male Opisthopatus only in the circum- 

 stance that in the latter the cruciform opening is contained between 

 four spiniferous tubercles instead of four tumid lips bearing primary 

 papillae ; while it differs from the opening in the female Opisthopatus 

 only in having the longitudinal slit much more strongly developed, 

 and generally about as large as the transverse one, the tumid lips 

 being similar in both cases. 



I also examined four smaller male specimens (one of which I 

 dissected) and two larger female specimens of P. novce-zealandicB 

 from near Wellington, N.Z. These specimens had evidently been 

 preserved in spirits without previous drowning. The sexual open- 

 ing, which was situated at the apex of a considerable eminence, had 

 in most cases the form of a longitudinal slit, which in one of the 

 females and in one or two of the males was bisected by a smaller 

 transverse slit, not detected in the remaining specimens. The 

 surface of the genital eminence was covered in the female with a 



* On opening these specimens they proved to be females like the others. I do 

 not know the male of this species. 



