GASTROPODA. 59 



separated by a deep, grooved suture ; their cross section is rectangular ; on the inside 

 of the whorls there are five spiral folds, of -which three are considerably stronger than 

 the other two ; there are two columellar folds of considerable development, the 

 anterior being larger than the posterior one; the other three are situated on the 

 posterior wall of the whorl, the middle one being the strongest of all ; the inner one, 

 very fine and sharp, the outer one broad and rounded. Body whorl somewhat 

 inflated, aperture not seen. Columella very short, apparently solid ; surface 

 smooth. 



Locality avd stratigraphical position.' — Mazar Drik. 



Bemarks. — This beautiful species is easily distinguished by the arrangement 

 of the internal folds from all other turreted species belonging to this genus. 



Nerinea reguieniana, d'Orbigny, is probably the nearest relation to this 

 species, but it is easily distinguished by having a fold on the outer wall, which is 

 entirely wanting in Nerinea ganesha, and only one fold on the posterior wall instead 

 of three as in the latter species. 



Pamily: cmiTHlD^. 

 Genus: CERITHITJM, Adamson. 



Ceeithium VISHNU, spec. nov. PI. XV. fig. 3. 



This is unfortunately only a fragmentary specimen, which merely serves for de- 

 scription, but, as the aperture is not preserved, the generic position remains some- 

 what doubtful. The shell apparently attained rather a large size, as the fragment 

 measures 65 mm. in height, with a diameter of about 34 mm. in the last whorl. 

 It is turreted in shape, with numerous whorls, which increase very slowly in height. 

 The whorls are slightly rounded and the suture is deep. The ornamentation consists 

 of thick, rounded longitudinal ribs, of which there are six to one volution, extending 

 from suture to suture. On the last whorl these ribs disappear at half the height. 

 There are besides some rather broad, flat, spiral bands, separated by narrow furrows 

 which run continuously over the ribs and interstices. There* are about five such 

 bands of the same strength on each whorl, and above them come three much finer 

 ones. On the spire and on the upper half of the last whorl three or four indistinct 

 longitudinal ribs are found between two primary ribs, producing low, rounded 

 tubercles on the spiral bands. On the lower half of the last whorl these bands 

 are, however, perfectly smooth. 



Locality and stratigraphical position. — Mazdr Drik, horizon 8. 



Remarks. — I cannot find any species that exhibits a similar ornamentation, 

 although there are undoubtedly forms in the cretaceous deposits of the Gosau 

 which show a similar diversity of stronger and finer longitudinal ribs. 



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