UNIVALVES. TURBO. 123 



DIVISION IV. SHELL DEPRESSED, FOLIATED, SPINOUS OR NO- 

 DULOUS, AND UMBILICUS LARGE, PERVIOUS, 

 AND ARMED WITHIN. 



Delphinus Dolphin, Exasperatus Granulated. 



Distortus Distorted. 



DIVISION V. CANCELLATED. 

 FAMILY 1. UmUlicated. 

 Scalaris Wentle-trap. 



FAMILY 2. Imperf orated. 



Principalis Many-ribbed. Lacteus Milky. 



Clathrus Latticed. Pulcher Beautiful. 



*Clathratulus Little. . Ambiguus Doubtful. 



Minute Shells. 



*Elegantissimus Elegant. *Coniferus Marginated. 



Simillimus Similar. *Denticulatus Toothed. 



Parvus Guernsey. *Arcuatus Margined. 



*Striatulus Wrinkled. *Striatus Striated. 



*Reticulatus Netted. *Costatus Ribbed. 



*Bryereus Bryer's. *Unicus Convex. 



Indistinctus Indistinct. 



DIVISION VI. SHELL WITH SUBCYLINDRICAL WHIRLS, SIMILAR 



TO THE LAST DIVISION, BUT NOT CANCELLATED. 



FAMILY 1 . Umbilicated. 



Crenellus Crenated. Limbatus Shouldered. 



* T hermalis Fresh- water. Carinatus Keeled. 



Labeo White-lipp' d. Separatista Three-keeled. 



Ligatus Ligature. Niveus Snowy. 



Foliaceus Leafy. Helicoides Brown-ziczag. 



FAMILY 2. Imperforate. 



Crenatus Crenated. Lincinus Green-and-purple. 



Elegans Elegant. Lunulatus Moon-spotted. 



o2 



