NO. 5 RHYNCHONELLOID BRACHIOPODS — COOPER 39 



Pedicle valve interior with remnantal dental plates and strong 

 corrugated teeth. Other details not yet known. 



Brachial valve with deep corrugated sockets, long falciform crura 

 attached to fairly broad outer hinge plates ; inner marginal rim pres- 

 ent on crura but no inner hinge plates ; socket ridges thick and curved. 

 No median septum. Other details not yet known. 



Type species. — Terebratula De Buchii Michelotti, Cenn. Brach., 

 Acefali foss. Italia, p. 4, 1938. 



Comparison and discussion. — This genus is characterized by its 

 smooth exterior, small, short beak, twisted to uniplicate anterior 

 commissure, nearly obsolete dental plates, and long falciform crura 

 attached to broad outer hinge plates. In the latter character and the 

 smooth, uniplicate shell Streptaria is like Basiliola but it differs in 

 beak characters, lack of a pedicle collar, and the small development 

 of the dental plates of the pedicle valve. 



Specimens of this genus are similar to Erymnaria in the smooth 

 exterior, beak characters, and the twisted anterior margin, but the 

 latter genus possesses two strong, diverging septa in the brachial 

 valve — a character unlike any other known rhynchonelloid from Terti- 

 ary rocks or Recent seas. 



Assigned species. — This genus is known in Mediterranean and 

 West Indian rocks. 



Terebratula De Buchii Michelotti, Miocene, Italy. 

 Rhynchonella deformis Seguenza, Miocene, Italy. 

 R. eocomplanata Sacco and var., Eocene, Italy. 

 Streptaria streptimorpha Cooper, new species, Eocene, Cuba. 



Distribution. — The known species of this genus are from the 

 Tertiary of Italy, southern Europe, northern Africa, and Cuba. 



Discussion. — One of the interesting features of Streptaria is the 

 twisted anterior margin. This character occurs in rhynchonelloid 

 stocks from Paleozoic to Tertiary times. It has been seen in many 

 different stocks and undoubtedly is an aberration of the anteriorly 

 produced folding that facilitates the passage of nourishing currents 

 into the valve and their elimination with waste from the valves. 

 Streptaria and Erymnaria form isochronous homeomorphs in this 

 respect. The Ordovician genus Streptis is like Streptaria in having 

 shells twisted to right and left but also has normally uniplicate indi- 

 viduals or species. 



Cuba has produced another species of Streptaria which is not de- 

 scribed because of insufficient material. Three specimens of this 

 undescribed shell are known from the Eocene of Camaguey Province 



