ShcKs from Lake Tanganyika. 95 



caiialiculatlon ; tlic outer lip is faintly effuse and prominent, 

 and the columellar tolds are similar and in the same position 

 in eacii. 



TurbomHa? terebriformis. 



Testa subulata, nitida, albo-grisea, supcrne pallide lilacca, oblique 

 costata et striata ; anfractus circiter 18, lente accrescentcs, a])i- 

 cales — ?, sequeiitL's .'J-4 couvcxi, longitudinalitcr tenuitor striati, 

 circa medium biangulati, ca^tcri convexi (superiorihus quara infe- 

 rioribus couvcxioribus, fortissime costatis), costis obliiiuis, sub- 

 acutis, distautibus, instructi, lineis increincnti teiiuissimis oblicjiic 

 flexuosis striati : anfr. ultimus ad peripheriam rotunde snbaugu- 

 latus, costis inferne obsoletis ; aportura loiigit. totius ^ adaequans ; 

 columella rectiuscula, supernc obsolete uniplicata. 



Longit. 12 millim., diam. 2^. 



The costce (about eight in number) on the upper wliorls are 

 stronger and further apart tlian on the lower ones, and are 

 more convex in outline ; on the last volution they number 

 about twelve or thirteen. The aperture is somewhat broken 

 away anteriorly, so tiiat the generic position of this interesting 

 species is not quite certain. The texture and costation some- 

 what recall the appearance of some species of Terehra. 



Streptostele Horei. 



Testa parva, elongata, anguste rimata, eerea ; anfractus 7|, apicales 

 laeves, cjeteri convexiusculi, sutura profunda leviter obliqua se- 

 juncti, costoUis confertis, erectis, supcrne ad suturam denticulati.s 

 instructi, inter costellus nitidi ; apcrtura racdiocris, longitudiiiis 

 totius \ suba?quaiis ; pcrist. iucrassatum, album, anguste refiexum, 

 margine externo prope suturam intus sinuato, columellari dilatato, 

 rimam semiobtegente ; columella indistincte contorta : paries 

 anfr. ultimi prope extremitatem labri tubcrculis duobis parvis 

 munitus. 



Longit. 6^ millim., diam. 2 ; apertura Ig longa et lata. 



This species is well distinguished by the fine longitudinal 

 riblels, which at the upper extremities give a finely denticu- 

 late appearance to the deep suture. The single specimen 

 under examination exhibits two denticles at the upper part of 

 the aperture upon the wall of the body-whorl — one near the 

 upper end of the upper lip, the other near it but further 

 within the mouth. The labrum is conspicuously sinuated 

 above near the suture and has a tubercular thickening within 

 below the sinus. 



