218 



whole shell, except a broad dorsal sulcus, covered with a smooth 

 enamel. Outer lip broadly inflected, not margined, smooth, with 

 eighteen to twenty narrow tooth-ridges ; inner lip with three 

 stout oblique ridges at the front, which are succeeded by 

 denticles. 



Dimensions. — Length, 4 ; width, 3 ; height, 2*5. 



Locality. — Miocene ; Muddy Creek. 



The few specimens under observation are slightly worn, and 

 may be mistaken for rolled examples of E. minor. In Eratopsis 

 it comes nearest in shape to E. nana, but it is broader, shorter, 

 and not granulated. 



FAMILY OVULID^. 

 Genus Simnia, Rissoa (1826). 



Simnia (Neosimnia) exigua, xptc. nor. 



Shell narrow-elongate, a little more than four times at long as 

 wide, shortly rostrate, and straight at both ends ; tapering reg- 

 ularly towards the bluntly-rounded posterior end from a point 

 between a third and a fourth of the whole length from the front ; 

 obliquely subtruncated anteriorly. Viewed from above, the left 

 profile is slightly arched, being almost straight ; on the right it is 

 nearly straight in the medial -third, thence gently curving to the 

 extremities, but more rapidly behind than to the front. The sur- 

 face is smooth, and beautifully spirally wavy-striate. 



The aperture is very narrow behind, gradually widening from 

 about the middle to near the front, where it again narrows, 

 though somewhat dilated. 



Columella distinct, sharply truncate in front, with a wide canal ; 

 posteriorly with a strong oblique callous fold. 



Outer lip thickened, margined externally, edentulous, medially 

 straightish, gently curved to the very short effusively dilated 

 posterior canal, abruptly curved to the short anterior canal. 



Dimensions. — Total length, 11-5; greatest width, 2*75; 

 height, 2. 



Locality. — Eocene ; Muddy Creek. 



By its narrow outline and short rostral prolongations the pre- 

 sent species comes nearest to S. acicularis, Lamarck, of the West 

 Indies, but apart from the posterior fold it appears to be a nar- 

 rower shell ; *S'. lanceolata, Sow., is narrower, but the extremities 

 are longer in proportion to the enrolled portion of the shell, and 

 it lacks the posterior fold. Not one of the recent species included 

 in the Section IS^eosimnia has the narrow profile of this fossil- 

 species ; Dall* remarks of Neosimnia. that " it is a convenient 

 section of Simnia, but the distinction between the two is very 



* Blake-Mollusca, vol. II., p. 234. 



