PALEONTOLOGY ZORRITOS FORMATION 159 



and casts show the same shape. The difference, should 

 there prove to be .such, can hardly be greater than varietal 

 in value. 



T. aequicincta is very similar to T. cyneglossula Harris 183 

 from the Claiborne Eocene, being only larger and less 

 arcuate ventrally,with finer concentric striae near the mar- 

 gins. Comparison of the hinge is not possible. Were the 

 sculpture of T. aequiterminata Brown and Pilsbry, 184 from 

 the Gatun beds, known, a resemblance to that form might 

 be found, the two being closely similar in shape. T. aequi- 

 cincta is very close to T. nitida Poli, 185 from the Pliocene 

 of Italy, the only apparent difference being in the ellipsoidal 

 bases of the concentric curves in the sculpture of nitida, 

 those of aequicincta being straight, and in the consequently 

 sharper upward curve of the sculptural lines posteriorly in 

 aequicincta. T. nitida is regarded by Sacco as an atavistic 

 development of the Miocene T. bipartida Basterot. The dif- 

 ferences pointed out between the other Tellinas here 

 described and T. cibaoica and maoica of Maury will make 

 clear the further distinctness of T. aequicincta from those 

 forms. The sculpture offers the chief point of variance. 



Lower to Upper Zorritos. Quebradas Heath, Zapotal, 

 de las Alturas. 



Section ANGULUS 



Tellina (Angulus) pressa Dall 

 PLATE X Fig. 4. 



Tellina sp. indt. B. Nelson, Trans. Conn. Acad., vol. 2, p. 201, 

 1870. 



Tellina (Angulus) pressa Dall, Trans. Wag. Inst, vol. 3, pt. 4, p. 

 1026, pi. 47, fig. 5, 1900. 



Tellina (Angulus) pressa Woodring, Bowden Ms. 



183 Bull. Amer. Pal., vol. 6, p. 161, pi. 49, figs. 15, 16, 1919. 



184 Proc. Ac. Nat. Sc. Phila., vol. 64, p. 517, pi. 26, fig. 5, 1912. 



185 Sacco, Piemonte, pte. 29, p. no, pi. 23, figs, na, b, 12, 1901. 



