TRANSACTIONS OF WAGNER 

 1466 



TERTIARY FAUNA OF FLORIDA 



comes elevated and laminar, and at each end of the left posterior ventral lamina 

 has a more raised portion, which might very well be termed a lateral tooth. 

 One of these is directly behind the ligament and the other fits into a depression 

 on the inner side of the bevelled posterior dorsal margin of the right valve 

 •very near its distal termination. I have not seen this development on any of 

 the typical Crassatellites, yet I imagine it must occur on some of them, since 

 Fischer in his Manual * speaks of " un dent cardinale posterieure rudimentaire" 

 behind the ligament in the right valve. As a cardinal tooth, as ordinarily de- 

 fined, cannot be situated behind the ligament in a Teleodont bivalve, this can 

 be nothing but the elevated edge of the upper end of the lamina referred to, 

 which is genetically the same as a cardinal. An examination of adult speci- 

 mens of Crassatellites plnmbeus, lamellosits, and a number of other Parisian 

 species shows that in them the obliteration of the third cardinal is generally 

 more complete than in most of the American forms of the same age, yet that 

 traces of it may be observed in several of them ; also that the type of the genus 

 (C. gibbosulus Lamarck, according to Bronn) belongs to the type named by 

 Conrad Pachythcerus, which is therefore an absolute synonym of Crassatellites. 



Crassitina Weinkauff is only the modern representative of Pachytharus, 

 and therefore falls into the same synonymy. 



Since the little shells which have been called Gouldia, Pseuderiphyla, and 

 Crassinella have preserved their characters through the greater part of the 

 Tertiary, it seems that they may properly be regarded as forming a valid 

 group, though these characters are not very marked, except in size and form. 



Excluding doubtful groups of Mesozoic age the following forms are known 

 to belong to this family : 



Genus Remondia Gabb, 1869. Type R. furcata Gabb, Comanche series. Cre- 

 taceous of Texas. 



Shell resembling Crassatellites, but compressed, with the ligament partly 

 external, the posterior third cardinal -of the right valve present, the posterior 

 margin of the right valve and the anterior of the left valve grooved to receive 

 the laterals of the opposite valve. 



Stearnsia {Robbinsi) White, 1887, is synonymous. 



Genus Crassatellites Kriiger, 1823. 



Shell solid, inequilateral, slightly inequivalve, usually subtrigonal, the pos- 

 terior end longer; valves closed, the ligament and resilium adjacent and in- 



' Man. de Conchyliologie, p. 1021, lE 



