- 200 - 



PEGTEK ( CnlillvIYS ) 3SLIIPIGTU3 n. sp. 



Description .- Shell small, thin, compressed, the height slip-ht- 

 ly exceeding the width; dorsal marrrins long; external scttlpture of 

 eleven feehle, romided rios, L;eparated b^- v/ider interspaces, becom- 

 ing obsolete on tbe dorsal half of the shell; concentric sculptiire 

 of fine, microscopic concentric striae over the entire snrf ace ; aur- 

 icles siibequal , the right anterior sciilptured vrith radials, with 

 superimposed concentric lines, scabrous along the hinge; byssal notch 

 prominent; interior of the valve with broad rndial unriiilations cor- 

 respondirig to the external intercostal spaces. 



Dimensions .- lat. 7 mm.; alt., 7.5 mm. 



Tie marte . - -i-'his s-pecies also is re'orenentert by a small right 

 valve. It is distinguished by its fev;, feeble ra dials and fine con- 

 Tentilc striae. Dall (l) has described a closely related form, ?, 

 alumensis , from the Ohipola ; it has more numerous and more promi- 

 nent raciials. 



(1). Trans. V^agner Free Iiist. Sci., Philadelphia, vol. 5, pt. 

 4, p. 740, pi. 34, figs. 10, 11, 1898. 



Ocourrenoe .- Lower Miocene: Bow den beds, Bowden, Jrmaica 



