ADDENDA. 99 



large, inflated, with small depressed tubercles, rather remote, and arranged in fine 

 encircling rows, the rows of tubercles are connected by delicate radiating lines, one of 

 which is united to each tubercle ; the base has a single, smooth, encircling keel ; the 

 aperture and inner lip are similar to those of Nerita minuta. 



A pretty little and rare species, with the tubercles rather distantly arranged in each 

 row, they are somewhat lozenge-shaped or pointed posteriorly, about fourteen occupying 

 an entire volution. 



Geological Position and Locality. The Great Oolite of Bussage, adjoining Bisley 

 Common, in the bed of white stone ; collected by E. Witchell, Esq. 



TROCHUS BURTONENSIS, Lye. Tab. XLV, fig. 16. 



Testa conica, laevigata, spira clevata, anfractibus (6), postice planatis antice concavis et 

 obtuse anyulatis, anfractu ultimo basi leviter convexa, imperforata, apertura subrotunda, 

 columella basi dente callosa. 



Shell conical, smooth ; spire elevated ; volutions (6), their posterior portions flattened, 

 the anterior portions concave, bounded by an obtuse carina, the last volution has the 

 base slightly convex, imperforate, but with an umbilical depression ; the aperture is 

 rounded ; the base of the columella has a thickened dental process. Small specimens 

 have the spire less elevated, and the bounding carina much less prominent. 



Geological Position and Locality. The Forest Marble of Burton Bradstock ; in the 

 collection of W. Walton, Esq. 



TURBO DEPAUPERATUS, Lye. Tab. XLV, fig. 13. 



PLEDROTOMAKIA PAGODUS, var. DEPAUPERATA, Gr. Ool. Mon., Pal. Soc., 1850, part 1, 

 pi. 10, fig. 9, p. 77. 



The shell figured in the first part of this Monograph as a doubtful variety of 

 Pleurotomaria pat/odus, Desl., has, by the aid of other specimens, been clearly shown to be 

 a different shell, which does not belong to the genus Pleurotomaria. Very few examples 

 have hitherto been obtained, all of which are more or less imperfect, have suffered com- 

 pression, or have been indifferently preserved ; however, by comparing one with another, 

 the distinctive characters have been fully ascertained. 



A Forest Marble specimen, slightly compressed, is now figured ; compared with the 

 original of the former figure the spire is less elevated, the ornamentation of the surface 

 and of the base are better preserved. 



The description formerly given applies to the species of Deslongchamps, the following 

 to Turbo depauperatus. 



Testa turbinata, spira elevata, apice obtuso, anfractibus (5) convexis, imprimis inornatis, 



