BRACHIOPODA. 



349 



texture ; the upper valve is almost flat, and pierced with 

 peculiar pores radiating to the circumference with branches 

 diverging to the surface. 



Hippurites. Lam. (Orthoceratites Picot de Lapey- 

 ronse.) — Shell tubular, rude, irregular, 

 attached ; lower valve cylindrical, more 

 or less lengthened, apparently divided 

 into sections by septa (considered by 

 some authors as merely projecting layers 

 of growth), having one or two lateral 

 tubes within ; upper valve round, flat, 

 fixed on the aperture of the tubular Hippurites cornucopia . 

 valve like an operculum. — Fossil. 



Dr. Mantell, who thinks it very doubtful whether this 

 shell is a bivalve or univalve, says they attain considerable 

 size in certain districts of the Pyrenees, where they abound, 

 and are called petrified horns by the inhabitants. The 

 description above is Mr. Sowerby's. 



Family 3. — CAPR O TINADJE. 



The lower or fixed valve is conical, spirally twisted, 

 and marked internally with prominent ridges, or transverse 

 septa ; the dorsal or free valve is oblique or spiral. They 

 are distinguished by the non-cellular or fibrous texture of 

 the shell. 



Caprotina. D'Orb. (Monopleura Matheron.) — This 

 genus seems to have been formed by D'Orbigny of a variety 

 of species belonging to other genera, such as Diceras, 

 Chama, Caprina, &c, and is said to be a " hopeless mass of 

 confusion." 



Caprinula. UOrb. — Shell free, testaceous, of a fi- 



