Mr. J. Lycett on a new species q/*Pteroceras. 309 



Prof. Jolin Phillips t figured Rostellaria composita, R. bispi- 

 nosa and R. ti-ifida^ from the oolitic rocks of Yorkshire. 



Mr. John Lycett described in a paper read before the Mem- 

 bers of this Society and now published J, five species of Rostellaria 

 from the inferior oolites of Gloucestershire, which he named 

 R. unicornis, R. simplex, R. spinigera, R. solida, and R. gracilis, to 

 which may be added three undescribed species from the shelly 

 freestone and oolite marl of Leckhampton. 



Messrs. Morris and Lycett will figure and describe twelve spe- 

 cies o{ Rostellaria (Alaria), and two species oi Pteroceras, from 

 the 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 M'hich 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 pi'eserved spider-like digitations give the shell a most sin- 

 gular appearance. I am indebted to my fi'iend 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 afiinities 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 Wrigktii. PL XIIL 



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, 



t Geology of Yorkshii-e, Part 1 . 



J Annals of Natural History, Second Series, vol. vi. p. 401. 



\ Palseontographical Society. 



