348 



POPULAR CONCHOLOGY. 



branches form a very obtuse angle, and unite at their 

 bases. — Fossil. 



These objects are not regarded as shells by some natu- 

 ralists ; the above description is Mr. Sowerby's. 



Caprina. U Orb. — Shell fixed, testaceous, and very 

 thick, the inferior valve of a lamellated texture ; superior 

 fibrous, inequivalve ; inferior valve conical and oblique, 

 fixed by its boss (crochet) ; marked in the interior by a 

 longitudinal groove * ; superior valve, very large, convex, 

 with a lateral hook or boss, which is sometimes spirally 

 turned; perforated throughout the greater part of its 

 length (proceeding from the edge), by a series of longitu- 

 dinal canals, some of them large within, others small on 

 the outside, all separated by vertical partitions; hinge 

 internal, and very complicated ; no ligament. Internal 

 apparatus formed in the inferior valve of a large conical 

 cavity, and a considerable number of horn-shaped conical 

 cavities formed by vertical partitions ; superior valve 

 divided in the interior into two large conical cavities, and 

 moreover provided in the region of the cardinal teeth with 

 a series of horn-shaped conical cavities corresponding to 

 those of the other valve ; all are circumscribed by vertical 

 thin plates. — Fossil. 



Mr. Sharpe is of opinion that this genus is allied to the 

 Chamacese — and has no connexion with Rudistse, or even 

 Brachiopoda. 



Family 2. — HIPPURITIDuE. 



The under valve of the shell is lengthened, almost cylin- 

 drical, gradually increasing in diameter, of a solid laminated 



* The " longitudinal groove" is in all probability for the ligament, 

 and therefore D'Orbigny is wrong in saying the latter does not exist. 



