23 St. IMai'rick and Claiborne Pelecypoda 23 



collection from near Negreet P. O., La. shows this feature in a 

 remarkable degree . The broad ribbed variet>- we have named 

 cainei, see below. Also see fig. 8, type of variety. From the 

 selJtvformis, light-colored layers near the base of the bluff at Clai- 

 borne thin, varietal forms are found, one of which herewith fig- 

 ured (fig. 5) is quite as large as the average desliayesi from the 

 .sends above. It is characterized b}^ the scaly spinosity of the bi- 

 partite ribbing shown on valves of ivillcoxi Yi'aW (fig. 6), and de- 

 scribed also as deshaysei \2ir. tinnus by de Gregorio. 



The intimate relationship of .some ioxwxs oi deshayesi ^vA wau- 

 tubbeanus may also be noted b}- the fact that the usual .small right 

 \'alves generally known as lyelli, in the collection of the U. S. 

 Nat. Mus. , No. 116,012, are classed 2iS wautubbeayiiis. 



Type. — U. S. Nat. Museum. 



Horizon. — St. Maurice Eocene. 



Specimens Jigured. — Wautubbee and Hickory, Miss. var. ; 

 fig. 5 from baseof bluff at Claiborne. 



Localities. — Simpkins place, 3 mis S. E. of Negreet, and vSt. 

 Maurice, La ; Wautubbee, Hickory, 8 mis W. of Enteri)rise, 

 Miss. ; 3 mis S. W. of Orangeburg, S. C. ; Coffeeville, ba.se of 

 bluff at Claiborne, Ala. 



Pecten (wautubbeanus var ?) willcoxi Dall, PI. 14. Figs. 6. 7. 



P. ( U'aiititbbt'atiHs) var. 7i'i//co.ri Dall, Trans. Wag. &c., vol. 3, 1898, 

 p. 737, pi. 29, fig. 4. 



Da IPs origi)taI description — Shell small, broad, flattish, thin ; left 

 valve with about sixteen narrow, rounded, elevated ribs, with somewhat 

 sparse, regularly spaced prickles on their tops ; between the ribs are similar, 

 but lower and smaller, non-dichotomous radial threads ; submargin very 

 narrow, nearly plain, with faint Cauiptonectes striation ; eans small, subequal, 

 except the byssal ear, which is longer, narrow, with a deep sinus and con- 

 spicuous fasciole, and about sixty scabrous radii, the right posterior ear with 

 concentric striae and only faint traces of a few radii ; the ears on the left 

 valve similar, with five or six .strong scabrous threads ; internal basal margin 

 of left valve with short flutings in harmony with the radial sculpture ; the 

 disk not grooved ; in the right valve the internal channels are more pro- 

 nounced ; the right hinge line has a single crural ridge parallel with the 

 margin on each side of the pit. Alt. 23, lat. 24 mm. 



This form is closely related to P. ecautubbeanus, from which it differs 

 by the isolated character of the prickles on the ribs, which are replaced in 

 7vautnbbea fills by more or less continuous concentric lamellation, while the 



