INSTITUTE OF SCIENCE, PHILADELPHIA. 293 



ceptible callus ; pillar straight, slender, perceptibly axially twisted. Lon. of 

 shell 6.0; max. diam. 2.75 mm. 



This species is smoother than most of the genus, but has the character- 

 istic features of Alaba. 



Family TRICHOTROPIDyE. 

 Genus TRICHOTROPIS Sowerby. 

 Subgenus Oerithioderma Conrad. 



Cerithioderma Conrad, Journ. Acad. Nat. Sci. Phila., 2d Ser. iv. p. 295, March, 1S60. Type 



and only species C. prima Conr., op. cit. p. 295, pi. xlvii. fig. 30. Eocene, Alabama. 

 .Mesosioina Deshayes, An. s. vert. bas. de Paris, t. 2, p. 416, 1861 ; ist species M. pulchra 

 Desh., op. cit. p. 416, pi. 28, figs. 13-16. Parisian Eocene. 



I have satisfied myself by an examination of Conrad's type that his 

 Cerithioderma is identical with Mesostoma. Deshayes's manuscript in my pos- 

 session indicates that the sheets containing that genus were printed in 1861 ; 

 Conrad's name, therefore, has priority, and must be adopted. 



Oerithioderma prima Conrad. 



C. prima Conr. supra vid. 



Mesostoma rugosa Heilprin, Proc. Acad. Nat. Sci. Phila. 1S79, P- 215, pi. xiii. fig. 13 ; 



Meyer, Ber. Senckenb. Ges. 1887, p. 18. 

 Mesostoma Lisbonensis Aldrich, MS. Eocene of Lisbon, Ala. 



Middle and Upper Eocene of Claiborne and Lisbon, Ala.; older Miocene 

 of the Orthaulax bed, Tampa, Florida ? 



The specimen from Ballast Point is in such a poor condition that it is 

 quite possible this provisional identification will not be confirmed. The speci- 

 men from Lisbon is heavier and larger than most of those from Claiborne, 

 and has fewer and stouter ribs on the last two whorls, but I think it is merely 

 an individual mutation of C. prima. C. rugosa Heilprin does not appear to 

 differ materially from C. prima. I have examined the types. The nucleus 

 of Cerithioderma is smooth, the first whorl and a half small, nearly flat above ; 

 the next whorl much larger, polished and inflated. 



I have described a recent species, C migrans, from eighty fathoms off 

 Havana, Cuba, which is very similar to the fossil form. As already noted, C. 

 spirata O. Meyer is a Litiopa. 



The genus is represented by several species in the Paris basin. 



Family MODULID.E. 



Genus MODULUS Gray. 



Modulus Gray, Synopsis Brit. Mus. 1842, pp. 60, 90 (name only) ; P. Z. S. 1S47, p. 150. 

 Turbinopsis Conrad, Journ. Acad, Nat. Sci. Phila., 2d Ser. iv. p. 289, Feb. -Mar., i860. 



Type T. Hilgardi Conr., Cret. Miss. 

 Pseudotrochus Heilprin, Trans. Wagner Inst. i. p. 114, 18S7. Not of Klein. 



There are two species in the Cretaceous greensand of New Jersey, one 



