EOMEGASPIRA. 187 



revolving posteriorly; columellar fold moderately developed, 

 bilamellate. Umbilicus minute. Length an inch, and a half, 

 breadth one-third of an inch. Inhabits Brazil." 



Genus EOMEGASPIRA Pilsbry, 1903. 



Megaspira DESHAYES, An. s. Vert. Bassin Paris, ii, p. 861. 

 Pyramidella sp. Michaud. 



Shell rimate or imperforate, long and gradually tapering 

 to a large, obtuse apex; composed of numerous (15 to 22) 

 narrow whorls, the last rounded peripherally and below. 

 Sculpture of sharp vertical rib-striae. Aperture small, irreg- 

 ularly ovate. Peristome incomplete, slightly expanded, the 

 columellar margin dilated above. Parietal wall bearing a 

 median parietal lamella, which enters about one whorl and 

 several smaller cord-like lamellae on both sides of it, the pari- 

 etal and sometimes an infraparietal emerging. Columella 

 3-folded, the folds becoming three high subequal lamellae 

 within, rapidly diminishing upward, and apparently not more 

 than two whorls long. Outer wall -bearing numerous strong 

 palatal lamellae, which penetrate scarcely deeper than the 

 last whorl. Axis slender and perforate throughout, smooth 

 above the penult, whorl. 



Type Megaspira exarata (Michaud) Desh., pi. 29, figs. 16, 

 17. Distribution, lowest Eocene of the Paris Basin and Lon- 

 don Clay; a small species in* the English Oligocene. 



The shell in this Eocene genus is intermediate in contour 

 between Megaspira and Cceliaxis; and like both, the axis, 

 though small, is hollow, and the apex obtuse and rounded. 

 The fine, sharp vertical striation resembles that of Cceliaxis. 

 The aperture is like that of Megaspira, especially in the tri- 

 plicate columella and the parietal lamella (concealed by 

 matrix in Deshayes' figure of exarata, which I have copied). 

 But it differs from Megaspira in having the lamellae all short, 

 not penetrating deeper than the penult, whorl, the axis above 

 that being smooth; in the development of numerous acces- 

 sory lamellae upon both the parietal and columellar surfaces, 

 and in the possession of palatal plicae, as in Ccelocion. There 



