white] ANNOTATED CATALOGUE. 53 



the color markings such as are seen to characterize several species 

 already noticed, and also the form referred to in the following paragraph. 



Associated with W. ( V.) Baptista in Northern Colorado, east of the 

 Rocky Mountains, is a form of Neritina which is closely related to N. 

 volvilineata, which being undescribed I propose for it the name N. 

 br uner i in honor of Mr. Lawrence Bruuer, who first discovered the 

 species. It differs from N. volvilineata in being somewhat more globose, 

 having a less elevated spire, and the inuer lips broader and less re- 

 treating. It is marked by revolving lines, somewhat like that species, 

 but they are sometimes obsolete. It is also ornamented by zigzag color- 

 markings. The type specimen is represented by Figs. 14 and 15 on 

 Plate 23. 



Associated with the foregoing is still another form, much smaller, 

 which seems to be the young of A r . volvilineata. It is without color 

 markings, and the inuer border of the inner lip is dentate. 



Although belonging to so early an epoch, these Laramie species of 

 Neritina are the latest members of that family of non-marine origin that 

 are now known to occur in North American strata. Consequently, no 

 others besides those mentioned come within the scope of this article. 



The typical form of Neritina has doubtless come down to the present 

 day by securing a congenial habitat along the changing coasts of the grow- 

 ing continent; but although the subgeneric type Velatella existed before 

 the inclosure of the Laramie sea, that sea seems to have embraced all 

 the forms of that type which survived during the Laramie period. When, 

 therefore, the waters of that sea became wholly fresh, that type, together 

 with others, seems to have been extinguished as a consequence. 



CEKITHIIDiE. 



Only a single species, referable to this family, which may be regarded 

 as a non-marine form, has been found in any North American strata. 

 It was obtained from the Judith Eiver Laramie beds, in the Upper Mis- 

 souri River region by Meek and Hayden, and by them described under 

 the name of Cerithidea nebrascensis.* Those authors referred it to the 

 subgenus Pirenella Gray, but they expressed some doubt as to the 

 true generic character possessed by the shell. Although Cerithidea is a 

 well known living genus of the Old World, this species at present 

 stands alone, or without near kuowu allies, either living or fossil, among 

 North American mollusca, if its generic relations are correctly under- 

 stood, as stated above. It is represented on Plate 26. 



MELANIID^E. 



Most naturalists agree in the opinion that no living North American 

 species of mollusca are properly referable to the genus Melania; 

 although formerly many species were referred to that genus which 

 are now placed in the family Ceriphasiidaj, and mostly referred to the 



* U. S. Geol. Sur. Terr., vol. ix, p. 559, pi. 43, fig. 9. 



