GASTEROPODA. 105 



ADDENDA. 



AMMONITES GRACILIS, Buckman. Plate XIII, figs. 2, 2a ; and Plate I, fig. 3. 



The description of this species is given at page 12, but the additional figure is here 

 given (Plate XIII, fig. 1,) to illustrate the form and general character of the more mature 

 shell, which differs considerably from the young state of it. (Plate I, fig. 3.) 



It has the general form of Am. Charmassei, D'Orb. ; but the costae in A. gracilis are 

 not interrupted over the back as in that species, and the volutions are more fully exposed. 



PTEROCERAS WRIGHTII. Plate XIII, fig. 1. 



P. Testa fusiformi, tumidd ; anfractibus (6) rotundatis, l&vibus vel spiraliter striatis ; 

 ultimo ffibbo, transversim carinato ; carinis tribus rotundatis incequaliter remotis ; in digitos 

 longiores productis ; dorso ad angulum tuberculin duabus magnis ; labro quinque? digito, 

 digitis in estate adultd longissimis, Jlexuosis, recurvatis ; caudd longissimd arcuatd. 



Shell fusiform, volutions 6, rounded and smooth, or faintly striated ; the body-whorl 

 inflated, and having three indistinct carinae developed on its upper surface, two of which 

 have a transverse prominent tubercle ; each carina leads to a digitate process ; labial wing 

 short, and terminating in four long slender flexuous digitations ; the first digitation ascends 

 close to the spire, and is attached to it ; it curves a little outwards, and then extends back- 

 wards an inch and a quarter beyond the apex of the spire, where it is broken off; 1 the 

 second curves gently outwards and backwards ; the third is broken off three quarters of an 

 inch from the labial wing ; a remaining fragment indicates that it curved gently outwards, 

 and is represented by a dotted line in the figure ; the fourth passes forwards for an inch 

 and a half, and then curves outwards ; the canal is long, and arched backwards. 



This fine fossil presents some points of resemblance to Strombus Oceani and S. Ponti, 

 Al. Brongniart, but the latter species has upwards of six carinae upon the last whorl. In size 

 it exceeds all the other Great Oolite examples of the Strombidce, and would seem to be very 

 rare. One specimen in the cabinet of the author, which has not the wing developed, and is 

 in other respects imperfect, is the only other known example. The present remarkable shell 

 is in the cabinet of Dr. Wright of Cheltenham, who has kindly communicated it, and to 



1 There are traces of another digitatiou between the first and second above described, arising near to 

 the base of the former, but apparently broken off in the specimen figured. 



