TRANSACTIONS OF WAGNER 

 702 



TERTIARY FAUNA OF FLORIDA 



of this horizon are all more or less distorted, and the shell may be the same, 

 as he originally thought it to be. The dentition of the hinge is similar to 

 that of many Pectens, such as P. Stviftii Bernhardi, P. vcntricosns Sby., and 

 P. purpuratus Lam. 



The third species referred by Conrad to this group is P. magnolia Conr. 

 (Pac. R. R. Rep., vii., p. 191, pi. I, fig. 2, 1857), of which the very imperfect 

 fragments which served as types are in the National Museum. The figure is 

 a very erroneous diagram compounded from the characters of these fragments. 

 A better specimen of the same species was later described by Conrad under 

 the name of L. crassicardo (Proc. Acad. Nat. Sci. Phila. for 1862, p. 291) but 

 has not been figured. The types are in the Academy's collection. Both 

 valves are convex and have the hinge-teeth moderately developed. The shell 

 has from eleven to fourteen ribs and much resembles P. Jcffersonius, except in 

 the greater development of the hinge-teeth and the radial ribbing of the ears. 



It grows even larger than the average Jeffcrsonius and belongs to the 

 Miocene of the Santa Inez Mountains, Santa Barbara County, California. 

 According to Gabb (Pal. Cal., ii., p. 105) a broken specimen of this species 

 served as the original for the figure of Spondylus estrellanus Conr. (Pac. R. R. 

 Rep., vii., pi. I, fig. 3, 1857), an opinion which the figure, poor as it is, offers 

 much to confirm. 



The genus established by Conrad was based on the heavy cardinal 

 laminae which compose a distinctly dentiferous hinge; this feature, however, 

 varies in the different species and is insufficient as a basis for a group of such 

 value in view of its inconstancy. The group name, whatever rank is assigned 

 to it, must depend upon the type. This, as already pointed out, belongs 

 among those species which unite with sculpture similar to that of P. maxiinus 

 the character of having both valves more or less convex, instead of having the 

 right valve flattened or even subconcave. Such shells are more or less inter- 

 mediate between ALqmpectcn Fischer and Pcctcn proper. 



In 1867 Conrad, with the forgetful ness which marked his later work, 

 produced the genus Lyropcctcn again, as if it was not already described, and 

 offers as a type L. crassicardo, one of his original species but not that origi- 

 nally indicated as the type. L. crassicardo, however, is a true member of the 

 group. But to this species he adds Pecten nodosus and its allies, which are 

 not entitled to be admitted. Fischer, in citing Conrad, ignores the original 

 description and mentions P. nodosus as the type, which it never was, and thus 

 subsequent writers were led into error. The modification of the original 



