210 Transactions of the Royal Society of South Africa. 



Genus Melanoides Olivier, 1807. 

 Melanoides tnberculatus (Miiller), 1774. 



1786. Nerita tuberculata MiilL, Chem., Conch. Cab. ix, 2, p. 189, pi. 136, 

 figs. 1261-1262. D.F. 



1860. Melania inhambanica Mts., Mai. Blatt. vi, p. 216, pi. 2, fig. 10. D.F. 



Hah. Mozambique. Mopera, R. Quaqixa (Stiililmann). 



L. Marques. Tette ; Inhambane (Peters) ; L. Pavi ; Lebombo Marsh, 

 Rikatla ( Junod) ; Zangwe Basin (Cressy). 



M. inha^nbanica Mts., which has long been acknowledged as identical 

 with tuberculatus. was originally differentiated on account of its greater size, 

 32 X 11 mm., while in D.-O.-A., 1897, von Martens mentions examples from 

 the Tanganyika Territory as large as 37 X 13 mm. These are smaller than 

 the biggest of Cressy's bleached series from the Zangwe Basin, one of which, 

 lacking the apex, measures 41-0 X 16-1 mm., while a smaller unbroken 

 example is 39-5 X 14-0 mm. 



Family ASSIMINEIDAE. 



Genus Assiminea Leach, 1828. 



Assiminea bifasciata Nevill, 1880. 



1880. Assiminia bifasciata Nev., Journ. As. Soc. Bengal, xlix, 2, 

 p. 162. D. 



Hah. L. Marques. Estuary of Nkomati River (Junod). 



The shells agree in all respects with the typical form from Natal. 



The radula * (text-fig. 28) has 58 rows of teeth, and is about 1-35 mm. 

 in length. Each transverse row contains nine teeth. The central tooth 

 has five cusps, borne on a broad but rather short base. The first lateral 

 tooth on each side is larger than the central, with a somewhat oval 

 basal plate ; it also has five cusps, the middle one being rather long. Next 

 there is a small, rather narrow tooth, without any distinct cusps, similar 

 to that which occurs in the more typical species of Assiminea. The third 

 tooth has about seven cusps, and a long, rather narrow basal plate. In the 

 fourth or marginal tooth the base is also long, but it is somewhat broader, 

 and bears fourteen or fifteen small cusps or denticles. The transverse rows 

 are -0225 mm. apart, so that while the long bases of the outer teeth overlap 

 one another to a considerable extent, those of the central teeth hardly do 

 so at all. 



Although differing from them in detail, the radula of this species is of 



* Described from a radula from Isipingo, Natal, mounted by the late Prof. Gwatkin, 

 ■who received the animal from Mr. H. C. Burnup of Pieterraaritzburg. 



