132 Trans. Acad. Sci. of St. Louis. 



Embryo of nearly five whorls, much higher than wide, more rapidly acumi- 

 nate toward tip, the upper two or three small whorls smooth, the lower 

 two with rather close-set and more or less oblique longitudinal riblets ; 

 species much larger, with relatively less abbreviated whorls and very 

 distinct incised lines of growth, the peripneral carina only slightly 

 below the middle of the spire whorls 4 



4 — The prominent subsutural carina separated from the still stronger per- 

 ipheral carina by a concave space having several fine spiral threads, 

 this surface being subequal to or only slightly shorter than the interval 

 separating the subsutural carina from the peripheral carina of the 

 whorl above; embryo large and conspicuous, the riblets strong. Length 

 of a specimen having 8 body whorls, 19 mm. ; width, 6 mm. Vicksburg 

 Oligocene (upper and lower). (= supramiriflca and tizis De Greg.) 



cochlearis Con. 



The strong and rather more acutely elevated subsutural carina separated 

 from the coarser peripheral carina by a relatively much shorter concave 

 space, which is always very much shorter than the interval between the 

 subsutural carina and the peripheral keel of the whorl above; sculpture 

 otherwise nearly similar, the embryo narrower and with more feebly 

 elevated riblets ; shell smaller in size and of slightly more slender form. 

 Length of a specimen having 6 body whorls, 8.6 mm.; width, 2.7 mm. 

 Red Bluff Eocene snbsimilis n. sp. 



Group II. — Embryo smallj obtuse and paucispiral. 



Embryo of nearly two whorls, very broad and obtuse at tip, the lower part 

 gradually acquiring some feeble and irregular longitudinal riblets; 

 shell moderately stout, attaining rather large size and thicker in sub- 

 stance, the lines of growth being conspicuously excavated; spiral 

 whorls each with a strong subsutural and a still stronger and 

 thicker submedian spiral carina, the concavity between them gradually 

 acquiring one or two fine spiral threads and the space below the subme- 

 dian a fine raised line which on the larger whorls gradually becomes a 

 carina equal in size to the subsutural. Length of a specimen of 

 about 9 body whorls, 27 mm.; width, 7.5 mm. Lower Miocene of Alum 

 Bluff, Fla • barretti Guppy 



Similar to the preceding, but much more slender in form and thinner in 

 substance, the embryo still smaller but rather less obtuse, of scarcely 

 more than a single whorl, the riblets not visible in specimens at hand . 

 Length of a specimen of II body whorls, 23.5 mm. ; width, 6 mm. Caloos- 

 ahatchle Pliocene of Shell Creek, Fla albida Perry 



I have not seen the types of barretti and albida, but assume 

 that the West Florida Miocene species, described above, is 

 identical with the former, as it appears to pertain to the same 

 geological horizon, and adopt Dr. Ball's identification for 

 albida. The latter author has recently (Trans. Wag. Inst., 

 Vol. 3, p. 28) confused these two species with the widely dif- 

 ferent cochlearis of Conrad. 



