- 2r:0 - 



pairs is greater than on the type of pap^' r aoei^s , describe'' from 

 Santo ^omingo. 'i?he immature valves are higher than v/ide; auri- 

 cles large, suheniml; exterior smooth except for faint, micro- 

 scopic Gsmptonectes strij-tion. Gince the ventral third of both 

 valves has been brolren off it is difficult to determine the char- 

 acter of the internal sculpture; iff pa.ired radials were present 

 near the ventral mar-'^-in, they are obsolete before reac^hing the 

 portion rrhich is preserved. 



The distinguishing features of pa pv race us are its somev/hat 

 ovate form, smooth exterior and psire'i internal radials. A recent 

 Antillean and Gulf form is referre"! to this species. I'he valii^'ity 



of Its sepf^ration from the I'iocene and Pliocene P. mortoni Piav- 

 enel (l), is doubtful, but that species is, hov/ever, usually larg- 



fl). ProG. Acad. ITat. S^i., Philadelphia, vol. ?, p. 96, 1844; 

 -uomey and Holmes, Pleioc. Pos. South Carolina, p. 27, 

 pi. 10, figs. 1, 2, 1855. 



er and more orbiculrr; P. l-i!^ia BroMi and Pilsbry (2), from Gatun, /" h 

 has the a"aricles depressed belo" the plane of the disk, '•^he re- 



(2). Proc. ACad. Hat. Sci., Philadelphia, vol. 64, p. 514, pi. 

 24, fig. 1, 1912 (= pGCten ( Amusium ) cf. I'ortoni .-^avenel, 

 Toula, Jahrb. K.-k. geol. Heichsanstalt, vol. 58, pp. 714- 

 716, pi. 26, figs. 8, 9, 1908. 



