Nigerian Eocene Mollusca. 49 



throughout with numerous close, microscopically fine, spiral striations which are 

 crossed by equally fine, deeply sinuated longitudinal lines ; sutural margins 

 small, rounded, delicately reticulate or microscopically beaded in earlier 

 growth ; between the posterior suture and peripheral carina or shelf are two 

 distant slightly elevated circlets with reticulate or beaded margins, according 

 to age ; base depresso-convex, surrounded by a prominent carination (following 

 the peripheral shelf), and two distant minor carinae ; aperture subquadrangular, 

 with two horizontal grooves within marking the external carinae in rear of 

 the base. 



DIMENSIONS. 



Alt. (approximate) ... ... = 113 millimetres. 



Lat. ... ... ... ... = 29 



REMARKS. This species is interesting as showing relationships to T. 

 transitoria of Mayer-Eymar x from the Lutetian of Egypt, and T. mortoni of 

 Conrad 2 from the older Eocene deposits of Maryland, United States, as also 

 occurring in the Alabama Eocene. From the first-named it differs in having 

 only two circlets on the posterior surface of the whorls instead of three or 

 four, in possessing a more pronounced peripheral carina and a rather deeper 

 sinuation at the labrum ; the spiral ornamentation is likewise much less evident 

 on account of its microscopically small character. The new species presents 

 a similar pagoda-like axis to T. mortoni, a shell much less prolonged, 

 however, and having only a single carina on the basal whorl being without 

 the second carination which forms the sutural margin of the previous whorls. 

 This elegant and finely sculptured shell is generally well preserved and 

 although the spires are never complete, there are fragments, exhibiting the 

 earliest period of growth in which a minute, rounded and smooth nucleus 

 can be traced. 



I have ventured to name this shell in honour of a well known palaeocon- 

 chologist of the United States, Dr. Carlotta Maury, the authoress of memoirs 

 dealing with Tertiary Mollusca from Trinidad, San Domingo, &c. 



OCCURRENCE. Cuttings Nos. i, 5, 6, 10, 12, 13. 

 COLLECTORS. Mr. Kitson, Sir F. Lugard. 



1 Palaeontographica, 1883, Vol. 30, pt. i, pi. 23, fig. 6, p. 76. 



2 Journ. Acad- Nat. Sci. Philadelphia, 1830, Vol. 6, p. 221, pi. 10, fig. 2. 



