370 



Shell white, of a depressed conical form, concentrically lamellar, 

 and radiately striated ; lamellae close-set ; epidermis hairy. 



Found by Mr. Cuming upon stones among coarse sand in seven- 

 teen fathoms water, near Lobos Island, on the coast of Peru. 



3. HiPPONYX suBRUFA (pi. Ixxiii. f. 21, 22, 23.) Sow. I. c. 

 Pileopsis subrufus. Lam. Patella subrufa, Billw. 



Testa aurantiaco-rufescente, subconica, concentrice sulcata, ra- 

 diatim striata, striis profuudis, marginibus sulcorum crenulatis; 

 vertice postice inclinato. 



Shell somewat conical, of an orange reddish colour ; concentri- 

 cally grooved and radiately striated, with deep striae; margin of 

 the grooves crenulated ; vertex inclined backwards. 



Pound with H. Mitrula, by Mr. Cuming. 



4. HiPPONYX RADiATA (pi. Ixxiii. f. 24, 25.) Gray, I. c. 



Testa subdepresso-conica, fulvescente, radiatim costata, costis 

 crebris, imbricato-squamosis ; vertice postico. 



Shell of a somewhat depressed conical form, and of a yellowish 

 brown colour, radiately ribbed, ribs very close and fine, with little 

 imbricated scales ; vertex posterior. 



Pound attached to rocks at Panama and the GaUapagos Islands, 

 by Mr. Cuming. 



5. HiPPONYX TiCAONiCA (pi. Ixxiii. f. 28, 29.) noUs. 



Testa suborbiculari, radiatim confertim striata, albida ; vertice 

 versus marginem postico-dextrum reflexo ; epidermide pilosa, ful- 

 vescente. 



Shell suborbicular, with close-set radiating striae, whitish ; ver- 

 tex turned backward toward the right margin ; epidermis hairy, 

 pale fulvous. 



Prom Ticao ; H. Cuming. 



THECIDIUM, Be France. 



Testa insequivalvis, aequilatera, valva altera gibbosa, ssepe rostrata, 

 imperforata, extiis affixa, altera plana operculiformi ; cardine ut in 

 Terebratulis ; ossiculo interno in valva plana intus affixo; area 

 cardinali magna, trigona. 



The principal circumstance which distinguishes this genus from 

 Terebratula is, that there is no perforation at the apex of the 

 deeper valve. It is found adhering to the Red Coral, in the Medi- 

 terranean. 



