116 PKOCEEDINGS OF THE MALACOLOGICAL SOCIETY. 



jequans ; labrum tenue, simplex ; columella leviter arcuata, supeme 

 reflexa, antice spiraliter torta ; lamina parietalis valida, prominens, 

 longe intrans. Long. 9, diam. 2-25 mm. ; apertura 2 mm. longa. 



Hab. — Buen Ayre (Hartert). 



The mammillated apex is often slightly out of the perpendicular. 

 I have much pleasure in associating Dr. Hartert' s name with this very 

 interesting and distinct form. On making a section of one specimen, 

 the parietal lamella was found to extend about a whorl and a half 

 inwards, the rest having been absorbed. The radula, kindly examined 

 by Mr. W. Moss, is Stenogyroid. 



8. CisTULA Eaveni, Crosse. 



Cidula Raveni, Crosse: Joum. de Conch., 1872, vol. xx, p. 159; 

 1873, vol. xxi, p. 43, pi. i, fig. 5. 



Hai. — Curagoa (Crosse). 



9. TuDORA megacheila, Pot. & Mich. 



Cyclostoma megacheilos, Potiez et Michaud : Gal. Douai, vol. i, p. 237, 



pi. xxiv, figs. 9, 10. 

 Cyclostoma megachilum, Pot. & Mich.: Pfeiffer, Conch. Cab., 2nd ed., 



p. 66, pi. ix, figs. 15-19. 

 Cyclostoma simile, Sowerby : Thes. Conch., vol. i, p. 103, pi. xxiv, 



figs. 48, 49. 



Mai. — Curagoa (Pfeiffer, Bland, Hartert). 



This species exhibits considerable variation in size. An average 

 specimen, consisting of four whorls, is 16 mm. in length ; a very 

 large example, having the same number of volutions, is 1 9 mm. long, 

 whereas the smallest specimen, which appears to be full-grown, is 

 only 10 mm. Between these forms there are many intermediate 

 specimens, so that a complete gradation in size is observable. 



10. TiTDOEA aueantiaca ("VVood). 



Turbo aurantius, "Wood: Index Test., Suppl., p. 19, pi. vi, fig. 23. 

 Cyclostoma aurantiacum, Sowerby : Thes. Conch., vol. i, p. 103, 



pi. xxiv, figs. 46, 47. 

 Cyclostoma versicolor, Pfeiffer: Conch. Cab., 2nd ed., p. 65, pi. ix, 



figs. 13, 14. 



Hab. — Buen Ayre (Bland and Hartert). 



Variable in colour, being uniformly white or flesh-colour, or trans- 

 versely lineated with brown, the lines more or less interrupted. The 

 largest specimen is 17 mm. in length, the smallest only 10"5mm. 

 "Wood's type, now in the British Museum (Natural History), is so 

 much worn that the surface of the three last whorls is almost smooth. 

 The two upper whorls exhibit the characteristic cancellated sculpture. 

 T. costata, Pfr., is very closely related to this species. 



