95 
Shells from Lake Tanganyika . 
canaliculation ; the outer lip is faintly effuse and prominent, 
and the columellar folds are similar and in the same position 
in each. 
Turbonilla ? ter ebr if or mis. 
Testa subulata, nitida, albo-grisea, superne pallide lilacea, oblique 
costata et striata ; anfractus circiter 18, lente accrescentes, api- 
cales — ?, sequentes 3-4 convexi, longitudinaliter tenuiter striati, 
circa medium biangulati, cseteri convexi (superioribus quam infe- 
rioribus convexioribus, fortissime costatis), costis obliquis, sub- 
acutis, distantibus, instructi, lineis incrementi tenuissimis oblique 
flexuosis striati ; anfr. ultimus ad peripheriam rotunde subangu- 
latus, costis inferne obsoletis ; apertura longit. totius -J- adsequans ; 
columella rectiuscula, superne obsolete uniplicata. 
Longit. 12 millim., diam. 2|. 
The costas (about eight in number) on the upper whorls are 
stronger and further apart than 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 that the generic position of this interesting 
species is not quite certain. The texture and costation some- 
what recall the appearance of some species of Terebra. 
Streptostele Horei . 
Testa parva, elongata, anguste rimata, cerea ; anfractus 7j, apicales 
laeves, caeteri convexiusculi, sutura profunda leviter obliqua se- 
juncti, costellis confertis, erectis, superne ad suturam denticulatis 
instructi, inter eostellas nitidi ; apertura mediocris, longitudinis 
totius | subaequans ; perist. incrassatum, album, anguste reflexum, 
margine externo prope suturam intus sinuato, columellari dilatato, 
rim am semiobtegente ; columella indistincte contorta ; paries 
anfr. ultimi prope extremitatem labri tuberculis duobis parvis 
munitus. 
Longit. millim., diam. 2 ; apertura \ \ longa et lata. 
This species is well distinguished by the fine longitudinal 
riblets, 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. 
