20 MOLLUSCA FROM THE GREAT OOLITE. 



nodules 6 in a volution, giving it a six-sided aspect. The last whorl has a single nodulated 

 carina, which has a prominence placed opposite to the aperture. The wing seems to be 

 but little produced, and is not divided into digitations. The canal is rather long and 

 straight ; the aperture ovate and contracted ; the left lip thin. 



This is a rare species, of which we have only seen about six specimens : all of these 

 have been more or less imperfect, the wing being badly preserved, or wanting altogether. 



Locality. The planking beds of Minchinhampton Common. 



ALARIA PARADOXA, Desl. sp. Plate III, figs. 9, 10. 



PTEROCEKA PARADOXA, Deslongchamps. 1842. M6m. Soc. Linn. Normandie, vol. vii, 



p. 170, pi. 9, figs. 16 18, 2022. 



Desk. Lam. An. sans Vert., 2d Edit., 1843, torn. 9, p. 682. 

 D'Orb. 1850. Prod. Paleont., p. 302. 



A. Testa parvd ovatd ; spird breviusculd obtusd ; anfractibus 7 angulato-nodosis, nodis 

 remotiusculis ; ultimo anfractu pluricostato, costis tran-sversis subtequidistantibus, et ineequa- 

 Jifjus; caudd brevi, recta ; aid angustd, varicem simulante, pluri-dentatd, dentibus inaequa- 

 libus subtiis canaliculatis, aperturd angustatd, varicemformante. 



Shell small, ovate ; spire moderately elevated, obtuse ; whorls angulated and nodulated, 

 the nodules being distant, or about 7 in a volution. The last whorl has plain transverse 

 ribs, nearly equidistant, and slightly unequal in size. The canal is short and straight ; 

 the wing is thickened into a kind of varix at the aperture, which is contracted. 



The spire bears a larger proportion to the last whorl than appears in M. Deslongchamps' 

 figures, which may be accounted for by his having restored the former' portion from another 

 specimen ; exactness in such a case is not to be expected. 



This species is comparatively rare. We have scarcely seen one which is perfect. 



Locality. Great Oolite of Minchinhampton. Bath Oolite (pierre blanche], Langrune, 

 Colleville, Normandy. (Deslongchamps.) 



ALARIA PARADOXA, var. Plate III, fig. 9 a. 



Shell ovate; spire moderately elevated; whorls (6) convex, rendered angular by pro- 

 minent tubercles, of which there are seven or eight in a volution ; the last whorl is large, 

 has numerous transverse ribs, of which two are more prominent ; the ribs terminate in 

 small digitations ; there is also a large bifid spine placed opposite to the wing, 



As compared with A. paradoxa, the spire is more elevated, and bears a larger pro- 

 portion to the body whorl ; the encircling ribs upon the last whorl are much more elevated 

 and unequal, the two larger ones giving a kind of bicarinated aspect to it, and terminating 

 in digitations, which are much larger than in the former shell. The large bifid spine upon 



