NO. 5 RHYNCHONELLOID BRACHIOPODS — COOPER 65 



missure, but there the similarity ends. The interior of Erymnaria is 

 so unlike that of Streptaria that confusion of the two is not possible. 



Geological horizon. — Eocene of Italy and Cuba. 



Distribution. — Two species of this genus are known in the Eocene 

 of northeastern Italy and one at the same horizon in Cuba. Only one 

 specimen is known from the latter occurrence but the interior details 

 visible through the shell make the identification with this genus quite 

 certain. 



Assigned species. — Three species of this genus are now known : 



Terebratula bolcensis Massalongo, Eocene, Italy. 



T. polymorpha Massalongo, Eocene, Italy. 



Erymnaria cubensis Cooper, new species, Eocene, Cuba. 



Discussion. — The genus is characterized by having strong support- 

 ing plates buttressing the crura and constituting the septifer type of 

 Rothpletz. It is the only Tertiary genus known to me having this 

 peculiar structure. The supporting plates of the crura make two 

 long, dark suture lines diverging from the beak. In several specimens 

 the socket plates are also visible as dark lines on the inner filling of 

 the shell. In such cases the socket plates occupy the outside and are 

 shorter than the crural supports. 



ERYMNARIA CUBENSIS Cooper, new species 

 Plate 19, A 



Shell of about median size for a rhynchonelloid, slightly wider than 

 long ; subpentagonal in outline ; widest at midvalve ; sides narrowly 

 rounded ; beak forming an angle of ioo° ; anterior margin truncated. 

 Anterior commissure strongly uniplicate; surface marked only by con- 

 centric growth lines. 



Pedicle valve evenly and gently convex in lateral profile ; nearly flat 

 in anterior profile with margins abruptly bent dorsally; umbo some- 

 what narrowly swollen ; median region flattened ; sulcus originating at 

 about midvalve, broad and shallow ; tongue moderately long, narrowly 

 rounded, and bent nearly at right angles to the lateral commissure; 

 flanks bounding sulcus narrow, gently convex, and moderately steep. 

 Beak small, rounded ; beak ridges not prominent ; deltidial plates con- 

 junct; foramen moderately large, longitudinally elliptical, and with 

 the anterior margin having a small lip. 



Brachial valve deeper than the pedicle valve ; gently convex in lat- 

 eral profile but narrowly domed in anterior profile, the sides long and 

 steep. Umbo and median region swollen ; fold originating anterior to 

 midvalve, low and gently rounded, scarcely protruding beyond the 

 flanks ; sides steep, gently inflated. 



