112 JURASSIC RHYNCHONELLIDS 
0-8 1:0 
Fic. 40. Transverse serial sections of “ Rhynchonella”’’ pyvenaei sp. nov. Topotype. 
Oxfordian. Pic du Gar, (Basses Pyrénées), France. (x5). 
Internal characters. Pedicle valve. The delthyrial cavity is subquadrate and 
limited by long, strong dental lamellae. Inner socket ridges are well developed ; 
lateral denticulae are present. 
Brachial valve. The median septum is strong and long septalial plates are 
developed. As seen in transverse section, the crura possess a very distinctive 
appearance through having “ knob-like ’’ structures median of the sharply pointed 
crural bases. 
DISTRIBUTION. Only known from the type locality. 
OccuRRENCE. All the material came from a bed about 10 cm thick where the 
species occurred profusely together with a lesser number of terebratulids. The 
matrix consisted of a very hard, dark limestone from which it was very difficult to 
extract specimens, 
