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ARC A (SOAPHARGA) IlTAilQuILATSRALIS Guppy. 



Aroa ina eg Txilate rails Guppy, 1866, Q-uart. Jour. Geol. Soc. London, 



vol. 22, pp. 29.'^-294, pi. 23, fig. 2. 

 Area inaequilateralis '^-appy, 1874, Geol. Kag., decade 2, vol. 1, 



p. 443, (check list). 

 Seapharca ( Scapharca ) inaequilateralis Guppy. Dall, 1898, Trans. 

 v?agner Free Inst. Sci., Philadelphia, vol. ?■ , 'ot. 4, 

 p. 647. 



Descripti on .- "Shell transverse, sli^tly oblicue, very in- 

 equilateral, produced posteriorly; valves with ahout 30 crenate 

 radiating ribs, single on the disk, v/here they are not broader th?3n 

 one-third of their interstices; double anteriorly and posteriorly, 

 7;here they are ecual in V7idth to the interstices; hinge-line long 

 straight, forming an abrupt angle m th the rounded anterior margin; 

 posterior margin v/ith an oblique slope." ( Gunp;- , 1866) 



Type locality .- Jamaica. 



Shell small, thin, elongate, subovate, moderately inflated; 

 umbones low, situated at about the anterior third of the length; 

 the straight dorsal margin forming sharp angles with both lateral 

 margins; angle between the dorsal and anterior lateral margin be- 

 ing slightly more than ^0°, the one betv.'een the dorsal and post- 

 erior lateral margins about 135^; en^treme upner portions of ant- 



