8 SUPPLEMENT TO GREAT OOLITE MOLLUSCA. 



Geological Position and Localitj/. The Great Oolite of Kirklingtoii, Oxon, collected 

 by J. F. Whiteaves, Esq. Eparcy, France. 



Cerithium? strangulatum, ^;Y7^mf. Tab. XLIV, fig. 2. 



A shorter and less cylindrical variety of this species was figured in the first part of the 

 'Great Oolite' Monograph, plate ix, fig. 18. The present specimen, which agrees more 

 nearly with the example figured by D'Archiac, has seven longitudinal costse, which are 

 conspicuous even to fhe base ; the contracted, pupseform aperture, with its prominent lips, is 

 ahke in both varieties. 



CeritJiium strangulatum, C. Bidimoidcs, C. spiciilum, and C. exi(/ua, belong to a small 

 group of minute, subcylindrical shells, with prominent, longitudinal costse, and small, 

 thickened, orbicular apertures, which have been referred to Cerithium and to Rissoa ; 

 perhaps eventually it may be deemed proper to separate them under a new generic 

 appellation. 



Geolopcal Position and Localitij. The Great Oolite of Minchinhampton Common ; 

 rare. 



Cerithium undulatum (var.), Pesl., sp. Tab. XLIV, fig. G. 



Melania undulata, I)esloii(jcJLamps, Mem. Soc. Linn, de XormauJ., 1842, vol. viii, 

 pi. 11, fig. 58, vav. a. 



Testa turrita ; avfractihus jjl^i^^is, transversiui striatis, ad suticras crenulatis, longitudi- 

 naliter costatis, in ultimo anfractii costis suhineurvis, basi obliqaa, striata; apertura 

 elliptica, obliqica, columella marf/inata ; labro sinistro jissuram umbilicatem obtigente. 



Var. a, testa breviori, costis et striis crassioribus, rariorisque. (Deslongchamps.) 



Shell minute, turretcd ; volutions flattened, transversely striated, crenulated near to 

 the sutures, and longitudinally costated ; aperture elliptical, oblique. 



Our example constitutes a small and short variety, with narrow volutions (about S) ; the 

 costa3 are large, straight, and from 7 to 8 in a volution ; they are most conspicuous near 

 to their upper extremities, which project, forming a kind of coronary border immediately 

 beneath the suture. Another minute specimen, apparently belonging to the same variety, 

 has the first three volutions almost plain, and the costas upon the succeeding volutions are 

 but little prominent. 



The typical form of tlie species figured by M. Deslongchamps has the costai much 

 more numerous and less prominent. 



Geolof/ical Position and Locality. The Great Oolite of Minchinhampton, collected by 

 E. Witchell, Esq. 



