Shells from Lake Tanganyika. 175 



Beymondia tanganyice nsis. 



Testa minima, imperforata, ovata, supernc acuminata, polita, sordido 

 cornea, infra suturara lineis duabu3 angustis oincta (una nivea, 

 altera inferiorc sed contigua nigresconte) ; anfr. 5, convexiuseuli, 

 ultimus magnus ; apertura irregularitor ovata, supcrne luvitcr 

 acuminata, longit. totius k subajquans ; peristoma paulo incrassa- 

 tum, margine esterno leviter patiilo, columellari valdo iucrassato, 

 expanse, superno labro callo tenui juncto. 



Longit. 3^, diam. 1| millim. 



This little shell appears to agree with Bourguignat's genus 

 Girandia and is probably closely allied to his G, ■prreclara. 

 That genus and Baizea^ also described by Bourguignat, appear 

 to be founded upon very trivial characters and not well dis- 

 tinguishable from Reymondia. Indeed, I am almost inclined 

 to believe that all of these so-called genera could well have 

 been dispensed with until more is known about the various 

 species which compose them. Tiie well-known genus lly- 

 drolna would, at present at all events, serve well for their 

 reception. 



Rissoa {Horea) Ponsonhyi. 



Testa parva, ovata, superne acuminata, imperforata, vix nitons, 

 dilute fusco-grisea ; anfractus 7, convexiuseuli, striis spiralibus 

 numerosis, lineisque iucrementi obliquia distinctis plus minus 

 cancellati, sutura subprofunda sejuneti, ultimus subglobosus ; 

 apertura inverse auriformis, longit. totius k fere asquans ; labrum 

 intus incrassatum, levissime patulum; columella infra medium albo 

 callosa, superne callo tenuissimo labro juncta. 



Longit. Gg, diam. 3| millim. ; apertura 3^ longa, 1| lata. 



The colour and sculpture of this interesting species recalls 

 certain forms of Plecotremay e. g. PI. concinna^ H. and A. Ad., 

 P. monilifera^ H. Ad., &c. 



I have created a new section of Rissoida? for it, as it does 

 not conveniently associate itself with any of the known groups, 

 and this {Horea) I have named in honour of Mr. E. Coode 

 Hore, the discoverer of this and many other new and inter- 

 esting Tanganyikan shells. It may thus be characterized : — 



Horea, subgen. no v. 



Shell small, ovate, transversely striated, and cancellated by 

 oblique lines of growth. Aperture with a thickened peri- 

 stome J columella also thickened. Operculum urdinown. 



