TEINOSTOMA. 259 



produced, elongate, remote from the axis ; peritreme rounded to- 

 wards the axis, sometimes angulate at the periphery. Obs. 

 Perhaps the natural position of this genus is in the family Um- 

 boiiida, the species more nearly resembling those of Ethalia than 

 any other group. In form and texture, however, they have very 

 great resemblances to the shells we have just passed in review. 

 An examination of the animal must determine the question. 



1. politum (pi. 256, f. 43, 44), A. Ad. — Testa orbiculato- 

 ovata, superne convexa, lactea, opaca, kevis, nitida; anfractibus 

 rapide crescentibus ; apertura elongata, antice valde producta et 

 acuminata ; umbilici regione callo magno kevi obtecta ; labro 

 supra anfractum penultimum reflexo. 05s. Tliis is the species 

 which served for the type of the genus as originally constituted. 

 It is a rare shell from the Philippines, and is in the Cumingian 

 collection. 



2. Carpenteri (pi. 25G, f. 41, 42), A. Ad. — Testa orbiculato- 

 ovata, superne convexa, lactea, opaca, lsevis, nitida ; umbilico callo 

 obtecto; anfractibus rapide crescentibus; apertura producta, 

 antice acuminata ; labro supra anfractum penultimum reflexo. 

 Obs. The only shell at all resembling this is T. ampleclaus, Cpr., 

 which however has a rounded aperture, whereas in this species it 

 is anteriorly produced. The spire is entirely concealed by the 

 last whorl, leaving only a minute pit at the apex, and the um- 

 bilical callus has a slight rimal fissure. 



'6. concentricum (pi. 256, f. 45, 46), A. Ad. — Testa orbicu- 

 lato-ovata, superne convexa, alba, solida, semiopaca, sulcis cou- 

 centricis confertis concinne insculpta, lineisque incrementi radi- 

 antibus subtilissiine decussata ; anfractibus rapide crescentibus, 

 ultimo dilatato, ascendente, alios involvente, vix usque ad apicem ; 

 peripkeria rotundata, basi convexa; umbilico callo convexo, laevi, 

 omnino obtecto ; apertura subciiculari, antice vix producta. Obs. 

 A solid convex species, with the surface finely concentrically 

 grooved, a peculiarity which distinguishes it from any of the 

 species already known. 



4. eadiatum (pi. 256, f. 47, 48), A. Ad. — Testa orbiculata, 

 depressa, superne convexiuscula, basi subplana, semiopaca, alba, 

 liueis incrementi raohantibus conspicue ornata ; umbilico callo 

 excavato angulato obtecto ; anfractibus subito crescentibus, ultimo 

 alios involvente usque ad apicem ; apertura, depressa, antice pro- 

 ducta. Obs. This species is distinguished by its depressed form, 

 and the conspicuous radiating lines which proceed from the axis 

 towards the periphery. The callus covering the umbilicus pre- 

 sents a sharp angular excavated edge near the inner lip. 



