47 
Fam. 1. Spiriferide. 
The oral arms very largely developed, and supported the whole of 
their length by a thin, shelly, spirally twisted plate. Only known 
in the fossil state. 
1. SprriFER (fig. 29). 
ze 
Fig. 29.—Spirifer 
Fam. 2. Rhynchonellide. 
The oral arms are elongate, fleshy, supported at the base by two 
short, hard, diverging shell-laminz arising from the hinge-margin 
of the ventral valve. 
1. RHYNCHONELLA. 
1. R. psittacea, t. 381. f. 2 (fig. 30). 
Fig. 30.—Rhynchonella psittacea. 
 @ 
Order IV. SARCOBRACHIA. 
The oral arms fleshy to the base, and without any shelly support. 
The lower valve without any processes on the hinge-margin or disk, 
or except sometimes a slight medial longitudinal elongation. 
Fam. 1. Productide. 
Shell generally spmose, attached by the surface of the ventral 
valve. Only found fossil. 
1. Propuctus. 
