NOTES ON THE CAMBRIDGE GREENSAND. 497 



tion of the several specimens proved this surmise to be correct, 

 Mr. Seeley's types answering exactly to the middle and upper por- 

 tions of the Gault specimen, which also possessed the angulated 

 body- whorl of the other Cambridge casts. 



The shell was consequently described by Mr. Gardner under the 

 generic name of Brachy stoma, and its affinities with the Aporrhaidse 

 duly pointed out. 



Chemnitzia tentjistriata. 



Cerlihlum tenuistr latum, Seeley, Ann. & Mag. Nat. Hist. 1861, 

 vol. vii. pi. xi. fig. 6. 



Pyrgiscus tenulstrlatus, Gardner, Geol. Mag. dec. 2, vol. iii. 

 p. 112. 



In his valuable paper on Cretaceous Gasteropoda above referred 

 to, Mr. Gardner describes some scalariform shells similar to the 

 C. tenulstr latum of Mr. Seeley, referring them all to Philippi's genus 

 Pyrgiscus, and deprecating at the same time the union of such 

 forms with the genus Chemnltzla. 



The reason which he gives for the revival of this genus, viz. the 

 want of columellar plaits, can hardly be regarded as sufficient, 

 especially as I find on referring to the ' Enum. Molluscorum Siciliae,' 

 vol. ii. p. 136/ that Philippi himself acknowledged its identity with 

 the Chemnltzla of D'Orbigny. 



It is difficult to understand why palaeontologists have ignored the 

 existence of the latter genus in Cretaceous rocks, when it is recorded 

 from Jurassic beds, and known in Tertiary and Recent times ; and I 

 cannot help thinking that many of the so-called Scalarlce are in 

 reality Chemnltzla?. 



Mr. Gardner's own description of Pyrgiscus is almost identical 

 with that of Chemnltzla in Woodward's ' Manual of the Mollusca,' 

 p. 239 ; and it essentially differs from Scalarla in the form of the 

 mouth, and by its incomplete peristome. 



It is remarkable that the two other species described by Mr. 

 Gardner are from the Folkestone Gault and the Blackdown beds 

 respectively; they are certainly all very closely related, and may, 

 I think, turn out to be varieties of the same form when more 

 specimens come to be compared. 



Turbo Pictetiantts, D'Orb. PL XXI. figs. 3-5. 



Turbo Plctetlanus, D'Orb. Pal. Fr. vol. ii. pi. clxxxiv. figs. 8-10 ; 

 Pict. & Roux, Gres Verts, pi. xix. fig. 1. 



Turboldea nodosa, Seeley, Ann. & Mag. Nat. Hist. ser. 3, vol. vii. 

 p. 289, pi. xi. fig. 14. 



The figures of Turbo Plctetlanus, both in D'Orbigny and Pictet 

 & Roux, fail to give an adequate idea of this shell ; and if Mr. 

 Seeley had never seen specimens he may be forgiven for not having 

 recognized the identity of the Cambridge fossil with the Perte-du- 

 Rhone form. 



Specimens now in the Woodwardian Museum, however, leave no 



