118 Dr. T. Wright on the Strombidre of the Oolites, and 



cies of Rostellaria (A/aria), and two species of Pteroceras, from 

 the 1 great oolite of Minchinhampton, in their forthcoming mono- 

 graph* on the fossil shells of that locality, some of which are 

 identical with Deslongchamps' species from Normandy. Those 

 species which have been identified in the oolitic fauna of Glou- 

 cestershire are marked with an asterisk. 



The Pteroceras which I have now the pleasure of exhibiting 

 was discovered in the Great Oolite of Minchinhampton ; it is by 

 far the largest and most remarkable form of that genus which 

 has been obtained from the oolitic strata of any country; its 

 finely preserved spider-like digitations give the shell a most sin- 

 gular appearance. I am indebted to my friend Mr. T. A. Young 

 of Dublin for the accurate drawing of the shell which accom- 

 panies this paper. 



The following description is by my friend Mr. Lycett, whose 

 extensive knowledge of fossil conchology well enables him to 

 point out the affinities of this new species. 



Pteroceras. 



Gen. Char. Shell oval-oblong, ventricose ; aperture oval, ter- 

 minating in a lengthened canal at both extremities, the anterior 

 in general bent outwards, the posterior taking the course of the 

 spire; right border in the adult thickened and developed into 

 a wing-shaped expansion, producing long digitate processes ; an 

 anterior sinus with a toothed border distinct from the canal ; 

 spire short, with the first digitation attached to it. 



Pteroceras Wrightii. Plate III. 



Shell fusiform, tumid ; volutions (six) convex and smooth, the last 

 volution inflated, having three obtuse gibbosities placed oppo- 

 site to the aperture, of which the first is the largest ; the outer 

 lip is expanded and divided into four branches or digitations, 

 which in the adult state are very long, flexuose, and nearly of 

 equal size ; the first digitation is attached to the spire ; it ex- 

 tends more than an inch beyond the apex, where it is broken 

 off; the second curves outwards and slightly backwards; the 

 third is broken off near to the wing, but a remaining fragment 

 shows that it curved outwards and forwards ; the fourth first 

 proceeds forwards and then suddenly curves outwards; the 

 canal is long and curved backwards. 



This fine species of Pteroceras appears to be nearly alone ; one 

 specimen in the cabinet of the author, without any labial expansion 

 and otherwise imperfect about the last volution, is the only other 



* Palaeontographical Society. 



