346 DESCRIPTIONS OF CARIBBEAN MIOCENE FOSSILS. 



While my friend Mr. Guppy repeats in his last publication his adherence to 

 Sowerby's fossil as distinct from the living shell, I propose to go further than ever 

 before, and add a species I described under another name eighteen years ago. 



They possess such marks of difference that perhaps the name might be retained 

 as varietal; but it certainly has no higher value. 

 A. (Barbatia?) Oronlensis, Gabb, n. s., PI. 44, fig. 21. 



Shell-moderate in size, elongate convex, umbones broad and placed in advance 

 of the middle ; beaks small, approximated, area narrow ; hinge line about three- 

 fourths of length of shell ; posterior end sloping convexly outward ; base broadly 

 and regularly rounded. Surface marked by about twenty-eight ribs of nearly 

 equal size, and all minutely tuberculated, especially on the middle of the shell. 



Figure. Barely magnified. 



Locality. From the black shale of Oronli creek, associated with Turritella, 

 Gatunensis, and Tellina Dariena. 



The generic reference is made entirely from the outline, since I have been 

 unable to expose a hinge. 



AXIN^A, Poll. 

 A. PECTINATA, Lam. 



Miocene, Sapote, Costa Rica, and also found living in the present West Indian 



waters. 



NUCULANA, Link. 



N. MiLLERi, Gabb, n. s., PI. 44, fig. 22, 22a. 



Shell minute, aliform; beaks two-fifths of length from the anterior end which 

 is rounded; posterior cardinal margin slightly concave, and bordered by a flat, 

 sloping area which extends to the posterior end. Posterior end prolonged and 

 acute, base broadly rounded. Surface marked by regular, fine concentric lines. 



Figure. Increased three times linear size. 



A single broken specimen from Mr. Miller, Sapote. 



PECTBN, Brug. 

 P. RUDis? Sby., Darwin's Geological Observations, S. A., PL 3, f. 32. 



An imperfect valve from the shore of the Reventazon river, a few miles above 

 Sapote. Specimen too imperfect for positive determination or figuring. 



P. THETiBis, Sby., PI. 45, fig. 23, 23a-b. 



id., Sby., Quart. Journ. Geol. Soc, vol. 1, p. 52. 

 Found with the preceding. Also in the Newberry lot from Gatun, 



