6 ' TKITON. 



RANELLA, Lamarck. Shell ovate or oblong, compressed, with two rows 

 of continuous varices, one on each side ; aperture oval ; columella 

 arcuated and ridged, or crenulated ; canal short, recurved ; outer lip 

 crenated. 



There are over fifty recent species. In the lingual dentition (PI. 2). 

 Triton and Ranella are closely allied, but with a difference in the 

 rachidian tooth ; Triton Cutaceum, however, approaches Ranella argus. 

 Distorsio (PI. 2, fig 9.) is not sensibly different from Triton. The 

 dentition of the family is unmistakably allied to that of the Cassididse, 

 Doliidse, etc. 



Fossil Genera. 



The distinctness of the following groups is very doubtful. 



RANELLINA, Conrad. The genus was never characterized. The type 

 differs from the figure in the varices being partially disconnected, thus 

 showing more affinity to Triton than to Ranella. 



RANELLA MACLURII Conrad . Plate 3, fig. 14. Tertiary ; Glaiborne, Ala. 



PERSONELLA, Conrad. Genus not characterized. Scarcely a Distorsio, 



but more like a Gutturnium. 

 DISTOKSIO SEPTEMDENTATA, Gabb. Plate 3, fig. 15. Eocene, Texas. 



TRITONOPSIS, Conrad. The type is a water-worn specimen, which Mr. 

 Angelo Heilprin, who has examined the shell, declares to be too 

 imperfect to assign to it any reliable characters. Has some resemblance 

 to the section Cabestana, like T. doliarium L. 



TRITON SUBALVEATUS, Conrad. Plate 3, fig. 30. Eocene, Vicksburg. 



TRACHYTRITON, Meek. The generic character appears to be confined 

 to the occurrence of internal varices, marking the former positions of 

 the lip, and which have not been absorbed when growth recommenced ; 

 otherwise very like Priene Oregonensis = cancellatus. The want of a 

 callus on the upper part of the columella, which Meek makes a distin- 

 guishing character from Priene, also characterizes the P. Oregonensis, 

 young, as described by Mr. Redfield. 



T. VINCULTJM, Hall and Meek. PI. 3, fig. 13. Cretaceous, Dakotah. 



Genus TEITON, Montfort. 



Animal of T. Tritonis, Linn., figured upon Plate 1 (Frontis- 

 piece). Details of the anatomy of the genus will be found in the 

 introductory portion of Vol. II of this Manual, together with 

 figures upon the 3d, 4th and 6th plates thereof. 



Shell oblong, with generally prominent spire, the whorls crossed 

 by a few remote and non-continuous varices ; the columella 



