162 Transactions of the Royal Society of South Africa. 



1898. Buliminus (Rhachis) pentheri Stur., S.A. Moll., p. 65, pi. 2, 

 figs. 47-48. D.F. 



Hab. L. Marques. Matolla {pentheri Penther) ; Mtisherra E. Valley ; 

 Dondo (Cressy). 



This gregarious species, described from Usagara, has a wide distribution, 

 having been collected, like Conulinus tumidus, as far north as the Shimbi 

 Hills by Kemp. 



The shells are very constant in contour, but vary greatly in fasciation. 

 The typical form has 2 bands, one at the periphery and one below it, and 

 the majority of examples from P.E.A. and the Shimbi Hills are of this 

 pattern, but some are unif asciate, lacking the lower band ; some are bandless, 

 approximating very nearly to melanacme Pfr., while others are trif asciate, 

 with an additional band midway between periphery and suture. All the 

 bands may vary greatly in breadth.* 



In 1897 von Martens listed usagarica as a variety of melanacme, while in 

 1889 Smith f stated that he considered it specifically distinct. I have not 

 seen the specimens on which the German author based his opinion, and am 

 fully prepared to admit that the two species may prove to be inseparable 

 when more topotypes of melanacme are available for examination, but on 

 the material before me it is certainly desirable to maintain distinction 

 between them. 



There is no doubt that pentheri must be placed in the synonymy of 

 usagarica, Dr. Sturany having kindly compared examples of the latter with 

 the type of the former and confirmed my view as to their identity. 



Rhachidina dubiosa (Stur.),- 1898. 



1898. Buliminus {Rhachis) dubiosus Stur., S.A. Moll., p. 64, pi. 2, 

 figs. 45-46. D.F. 



Hab. L. Marques. Matolla (Penther) ; Dondo (Cressy). 



Very closely allied to R. braunsi (Mts.), with which a more extensive 

 knowledge of both species may prove it identical. 



Rhachidina mozambicensis (Pfr.), 1846. 



1846. Bulimus mozambicensis Pfr., Symb. iii, p. 85. D. 

 1849. „ „ „ Rve., Conch. Icon., pi. 58, fig. 328. 



D.F. 



Hab. Mozambique (type in coll. Cuming ; Ancey ; Gibbons). 

 L. Marques. Rikatla (Junod). 



* Since above was in print, I have seen a rare mutation from the Shimbi Hills, which 

 has no upper bands, but four broadish ones between the periphery and umbilicus. 

 t P.Z.S., p. 586. 



