scHucHERT.] BRACHIOPOD TERMINOLOGY. 77 



Umbonal slopes. — The inclined surfaces about the umbo and opposite 

 the cardinal slopes. 



Ventral valve. — The valve situated on the ventral side of the animal, 

 and having in youth or maturity a delthyrium or pedicle opening 

 throngh which the pedicle is protruded, except in Iphidea, Obolella, 

 Lingula, etc., where the pedicle x)rotrudes between the valves. When 

 the shell is cemented to foreign bodies it is always by the ventral 

 valve. It is usually the larger and deeper of the two valves. Pedicle, 

 larger, dental, neural, and receiving valves are synonymous terms. 



