GENUS PYRAMIDELLA. 3 



this mollusk differs essentially from the animal of the AURICULA, 

 by the presence of the operculum, which we have just mention- 

 ed, and by the situation of the pulmonary organ, which is a true 

 branchia ; nevertheless, in other respects, the characters of the 

 shell have the greatest analogy with some specimens of this last 

 family. 



Sowerby, in his Genera, proposes to bring back to the PY- 

 RAMIDELLA, several species of shells, some of which are com- 

 prised among the AURICULAE ; I am not of the opinion of this 

 author ; these species do not appear to me to unite the charac- 

 ters observed in the genus which I have just described. As to 

 the number of folds, which he supposes to vary, I have always 

 found the same in all the specimens I have been able to examine ; 

 and the folds upon the columella, being a distinctive character 

 in this genus, it does not appear consistent to admit shells 

 which are destitute of them. Besides, what appears to me un- 

 answerably to establish an exact distinction between these differ- 

 ent shells, those of the family PLICJ1CEJ1 are marine and oper- 

 culated, while the others, on the contrary, live in fresh water, 

 and are destitute of an operculum. 



The species of the genus PYRAMIDELLA are not numerous. 

 The shells are generally quite small, of an elegant form, elon- 

 gated, marked with more or less deep spots. The animals are 

 very timid. No species has as yet been met with in our seas. 

 They appear to live in those of India, and upon the coasts of 

 Africa. 



1. PYRAMIDELLA TEREBELLUM, LAM. The Gimlet Py- 

 ^ , , ramidella. n f.fJ^jfTj 



(Collect. MASS. LAM.) LIST., Conch., t. 844, fig. 72. 



J /k&, *&5h{ . 



PL I, fig. 2, et fig. 3 Pomted.^^ &^& 

 P. testA conico-turrita, umbilicata, laevi, alba, lineis rufis cincta ; colu- 

 mella recurva ; labro inttis laevigato. 



Shell conical, turreted, polished, elongated, slightly transpa- 

 rent, white, beautifully adorned with transverse reddish or 

 brown bands, three in number upon each whirl, and four or 

 five upon the lowest, which is more inflated ; the middle band 



