TRANSACTIONS OF WAGNER 

 1516 



TERTIARY FAUNA OF FLORIDA 



explained, though Detken in his reprint (stated to be absolutely unchanged 

 from the original) places the synonym after the next preceding name in the 

 list. In 1855 Carpenter separated Clidiophora and in 1864 he published a brief 

 revision of the genus. The type originally named Solen inaquivalvis by Linne 

 was transferred to Tellina in the twelfth edition of the " Systema Naturae," 

 and was subsequently named Pandora rostrata by Lamarck, a name which has 

 been widely used. Because, after stating that the genus was founded on the 

 Linnean species by Hwass, Chemnitz queries whether his own Anomia cenig- 

 matica might not belong to it is not a reason for rejecting Hwass's name, as 

 mistakenly claimed by Fischer in his " Manual," otherwise we should have to 

 adopt Calopodium. 



The characteristics of the anatomy have been already mentioned (p. 532), 

 but some consideration may be given to the hinge. 



The beaks of Pandora are erect, and in the adult always more or less eroded. 

 The ligament and resilium lie initially beneath them. The latter is usually 

 longer, wholly submerged, and separate from the ligament except at its start- 

 ing-point. It is set in a groove, oblique or nearly vertical, and the edges of 

 the groove are usually a little raised. On the anterior side of the ligament, 

 when present, is to be found a long, strap-like lithodesma. In Pandora s. s. 

 and Ccelodon there is no lithodesma developed. The normal number of teeth 

 or laminae in each valve would appear to be three, but they may be merged in 

 the cardinal border or the raised edge of the chondrophore, so that in Pandora 

 s. s., when adult, the left valve appears to be without teeth and the right 

 valve has only two. The teeth are formed, as in other cases, of a shank or 

 lamina and a hook. Usually these become separated at an early age, forming 

 two separate teeth, but in Ccelodon the anterior left cardinal not only retains 

 its connection with its " hook," but as the shell grows the entering angle be- 

 tween the hook and shank, by the fusing of the distal edges of the laminae, is, 

 as it were, partially roofed over, a feature of which the most conspicuous ex- 

 amples in other groups occur in the Mactrida. The formulae are as follows : 

 Clidiophora, L - Ioriol ; Ccelodon, L - IoroAo : Pandora, k- oro1 . The anterior left 



R. oiroioi R. oinoi L. irio 



cardinal in the latter is represented only by a callosity on the anterior dorsal 

 border of the valve in front of the umbonal notch. In all the groups the laminae 

 have a tendency to pedunculation, the bases being narrower than the distal 

 portion. They are therefore very liable to be broken off in opening the valves 

 and are sometimes so interlocked that the animal itself can open the valves but 

 to a trifling extent. The ligament is short and black; it usually appears to 

 extend over the upper ends of the laminae in a horizontal direction or it may 



