4 MELVILL & STANDEN, Mollusca from N.E. Rhodesia. 



We may add that, although this very interesting col- 

 lection is small numerically, yet but few similar gatherings 

 from tropical Africa made at one time and under similar 

 circumstances much exceed it in actual count of species. 



Vast numbers of individuals, identical specifically, 

 occur in certain favoured spots, accumulated together and 

 gregarious, but there does not seem to be the wealth of 

 variety that is obtainable in many other parts of the 

 world, several of them of lesser area, if such an excep- 

 tional locality as Lake Tanganyika and its peculiar 

 quasi-marine fauna be not taken into account. 



Class GASTROPODA. 

 Fam. Cyclostomatid^e (Pomatiasidse). 



Pomatias nyassanus, Smith. 



Pomatias nyassanus, E. A. Smith, Proc. Zool. Soc. Zona 7 ., 1899, 

 P- 59 1 . P L 35>% 5- 



Hab. Petauke ; living good examples at 2,400 feet. 

 Mterize River, Loangwa, one, dead, at 2,000 feet. Also 

 good, but dead, specimens from the banks of the Loangwa 

 River, lat. 15° 30', at 1,700 feet. 



This species is conspicuous for its many close and 

 prominent spiral carinse. In this it to some extent ap- 

 proximates to P. transvaalensis (M.&P.) and P . phiriliratus 

 (Fulton), both species occurring further South, but the 

 riblets on these latter species are not so pronounced. It 

 is really nearer P. insularis (Rve) or P.]i<zmastoma (Anton). 

 P. letourneauxi (Bgt.) and P. zanguebaricus (Petit) from 

 contiguous neighbourhoods, are likewise akin. It is 

 probable several of these species occur in Rhodesia. 



