4.30 NEW YORK STATE MUSEUM 



PLATE 18 



Genus tropidocyclus De Koninck 



Page 330 



Tropidocyclus hyalinus sp. nov. 



Page 331 



i, 2 Apertural and dorsal views of a replacement showing the trilo- 

 bation of the stoma and back, due to the median ridge. X5 



3 Side view of a smaller shell. X5 



4 Side view of an entire shell showing the form of the aperture, 



the degree of umbilication and the character of the surface 

 markings, xj 



Naples subprovince Honeoye lake 



Genus caixonema Hall 



Page 337 



Callonema filosum sp. nov. 



Page 337 



5 The original specimen. X5 



Chautauqua subprovince Smith's Mills 



Genus loxonema Phillips 



Page 332 



Loxonema noe Clarke 



Page 332 



6, 7 Very young shells with convex and essentially smooth whorls ; 

 enlarged about 13 diameters 

 8-10 Essentially entire shells, all replacements in barite. X3 

 Naples subprovince 



Localities about Naples and Honeoye lake 



Loxonema danai sp. nov. 



Page 333 



1 1 A shell overgrown with Aulopora. X2 

 12, 13 Two examples showing the numerous whorls and the obscure 

 surface markings. X2 

 Chautauqua subprovince Forestville 



