2 GENUS PYRAMIDELLA. 



Quoy and Gaimard, to whom we are indebted for a knowledge 

 of these animals, suppose that they have the sexes united in an 

 incomplete hermaphroditisrn ; these writers have not been able, 

 satisfactorily, to examine the organs of generation. 



The general color of the body of these mollusca, is of a dull 

 white. The operculum only, and the edge of the mantle are 

 yellowish. 



Lamarck, in his Histoire des Animaux sans vertebres (1801), 

 first formed the genus PYRAMIDELLA from the TROCHUS dola- 

 bratus of Linnasus, and the BULIMUS terebellum of Bruguiere ; 

 he placed it between MELANIA and AURICULA, considering the 

 species which composed it, as fresh water shells. Some years 

 after he suppressed this genus, and again re-established it in 

 the compendium of his course in 1811 ; but during the inter- 

 val elapsing between these two periods, De Roissy and Montfort 

 had retained and admitted it, one in Sonnini's Buffon, the other 

 in his Conchy liologie Systematise ; and when, in 1811, La- 

 marck, after a more mature examination, coincided with them, 

 or rather acknowledged the justness of his first opinion, he 

 approximated the genus TORNATELLA to the PYRAMIDELLA, and 

 thence formed a family under the name of PLICACEJL; the 

 analogies which he found between these two genera, by blending 

 them, induced him to place them near to the MACRO STOMJE 

 and the SCALJ1RIJE ; this little family has appeared established 

 so naturally, that it has remained almost unmodified, in the 

 principal systems published since that time. 



Cuvier, in the first edition of his Regne Animal, placed the 

 shells of this genus in the family of the AURICULJE; this decision 

 was followed by Ferussac, in his Tableau systematique ; but in 

 the second edition of the Regne Animal, its illustrious author 

 concurs with the opinion of Lamarck, in bringing these two 

 genera into the family PECTINIBRANCHIATA, among the 

 MELANUE and the JANTHINJE. 



Blainville, Traite de Malacologie, p. 453, arranges them 

 among his J1URICULJE, and has not adopted the division PLI 

 CJLCEJL of Lamarck ; but, afterwards, becoming acquainted with 

 the operculum of the animal of the TORNATELLA, this writer 

 judged that it ought no longer to hold the place which he had at 

 first assigned it, without, however, pointing out another. In fact, 



