250 Bulletin 39 42s 



Tellina {Merisca) crystallina Dall, 1901, Proc. LT. S. Nat. Mus,, voL 



23. P- 3", Pl- 2, fig. 10. 

 Tellina {Merisca) crystallina Maury, 1917, BulL Amer. Pal., vol. 5, p. 



3S7, pi. 38, fig. 4. 



This Tellina, the type of the section Merisca, is recognized 

 by its thin, depressed shell, strongly sculptured with distant, but 

 regular, raised, concentric lamellae. It is ver}^ rare as a fossil, 

 our collection containing but a single specimen from the Gatun 

 beds of the Banana River. It has previously been recorded by 

 Maury as a Miocene fossil in Santo Domingo. 



In the recent fauna, Tellina crystalliiia is distributed along 

 both the Atlantic and Pacific coasts of Central America. I have 

 collected a few specimens from the beaches of Bocas Island and 

 more abundantly at Bucaru, Province of Los Santos, on the 

 Pacific side of Panama. 



Gatun Stage: Hill No. 2. Banana River. 



Tellina nasua, n. sp. Plate 26, figure 17 



Shell sub-rhomboid, slightly convex, thin; beaks small, in- 

 conspicuous, posterior to the middle; the anterior end longer, 

 the dorsal-anterior dorsal margin descending, the extremity 

 rounded into the gentle curve of the base; (the posterior side 

 broken in the type specimen); the greatest convexity of the shell 

 lies along the broad, umbonal slope anterior to the beaks; the 

 surface is finely sculptured with regular, sharp, concentric 

 ridges, separated hy narrow, band -like interspaces; interior of 

 the right valve with a large pallial sinus which extends to the 

 anterior ^ of the shell; hinge appearing normal for the section, 

 but partl}^ broken away, but showing a large anterior lateral 

 tooth. 



Length 20 ? Height 15.25, diameter of the right valve 

 3.00 mm. 



Our specimen if fragmentary, the posterior portion of the 

 shell being broken away. There is however little doubt that 

 the species is a true Merisca, allied to T. cequistriata Say and 



