South' African Land- Moll asca, 579 



Species of the Genus MlCR0KERKU3. 



Microherlciis ni/Dunetricus, Craven. (PI. I. figs. 2, 2 a, 

 animal ; VI III. fig. 4.) 



Localiti/. Pretoria (No. 4), 



i>\\v\\ globosely conoid, thin, riniate ; sculpture very in- 

 uistinct longitudinal streaking, with well-seen lines of trans- 

 verse growth ; colour ochraccous, with a yellow tint; spire 

 conic, apex blunt; suture shallow; whorls 4, somewhat 

 rapidly increasing, and tumid, the last rounded on the peri- 

 phery ; aperture wichly lunate ; peristome veiy thin ; colu- 

 melhir margin not thickenetl, subvertical, a slight reflection 

 near the umbilical region. 



8ize : major diam. 14"6, minor diam. 12'4 ; alt. axis 7*5 mm. 



Ponsonby and (/onnolly both agree that this species, No. 4, 

 and that provisionally named concintms from Boksburg, near 

 Johannesburg, are the same. 



In No. 4 tube 1 found two species, with locality Pretoria; 

 in two of the specimens the animal was not removed from 

 the shell, and the largest I dissected. 



The remaining three specimens must be Zingis natalensis, 

 as given in tlie list of specimens sent me by Mr. Burnup ; but 

 what the shell is like it is impossible to say, or to which of 

 the two species his following notes apply: — 



"This has been identified as Zingis natahnsis,Vh\, hnt 

 local collectors doubt the accuracy of tlie determination, and 

 I think Mr. Ponsonby now shares the doubt. As the true 

 Zingis natalensis, Pfr., is a common shell at Port Elizabeth, 

 its anatomy is probably known, but in any case one of 

 Mr. Ponsonby's correspondents is likely soon to supply you 

 with examples." 



Animal. — Lobe over the mucous pore (PI. III. fig. 4) at 

 the extremity of the foot only moderately long, the right 

 s!iell-lobe (PI. I. fig. 2) long and very narrow, the left shell- 

 lobe (fig. 2 a) triangular, small. 1 he left dorsal in two 

 parts, the posterior the largest. The visceral sac on tiie 

 anterior part pale-coloured, with short narrow white streaks 

 extending as far as the kidney; distant rather large spotting 

 follows and continues to the apex. Liver a pale grey-brown. 



The generative organs (Plate in next part), although gene- 

 rally like the other species of this South-African subfamily, 

 differ in detail : the accessory organ is very close to the 

 retractor muscle, the flagellum is shorter, and at the head of 

 the shaft of the penis there is a sharp bend concealed some- 

 Avhat by muscuhir tissue. The Sj)ermatheca contained a 



