THE CAMBRIDGE GATTLT AND GREENS AND. 289 



Hamites viegtjlattjs, D'Orb. 



Harnites virgulatus, D'Orb. Pal. Fr. i. p. 545, pi. 134. f. 1-4 

 (Brong. ?); Pict. & Roux, Gres Yerts, pi. 14. f. 7-9; Ste.-Croix, p. 85, 

 pi. liv. f. 6-12. 



M. Pictet (Ste.-Croix, p. 85) was the first to recognize this species 

 as existing at Cambridge. It is characterized by the possession of 

 comparatively few, strong ribs crossing the shell nearly at right 

 angles to its axis, and interrupted at the edges of its internal face, 

 which they leave perfectly smooth. 



It is a common fossil, occurring in all collections ; I have also 

 seen it from the Folkestone Gault. 



Hamites intermedins, Sow. 



Hamites intermedins, Sow. Min. Conch, pi. 62. f. 2, 3. 

 H. attenuatus, D'Orb. (? Sow.), Pal. Fr. pi. 131. f. 9-13. 



I am inclined to think that H. intermedins and H. attenuatus are 

 only different parts of the same shell. Sowerby (Min. Conch, p. 135) 

 describes Hamites as hooked, or bent into two parallel limbs ; while 

 D'Orbigny figures three limbs, saying at the same time (p. 535) that 

 Sowerby's H. tenuis, H. attenuatus, and H. compressus are parts of 

 one form. Instead of compressus I should rather be inclined to 

 substitute H. intermedins, as having nearer relations with the other 

 two ; and this is Prof. Eenevier's opinion (see Faune de Cheville, 

 p. 104), except that he appears to have some doubt as to the iden- 

 tity of D'Orbigny's and Sowerby's H. attenuatus. H. compressus he 

 considers to be a separate species ; but the whole of this genus re- 

 quires further investigation. 



Turrilites Wiestii, Sharpe. 



Turrilites Wiestii, Sharpe, Ch. Moll. p. 68, pi. xxvii. f. 8, 9. 



The specimens which I have identified with this species have been 

 named T. Bergeri in the "Woodwardian Museum ; they are, however, 

 clearly distinguished from that species by possessing only three 

 ranges of tubercles, one sutural and two free ; the transverse ribs also 

 which bear the tubercles are not so numerous as in T. Bergeri, and are 

 more distinct above the uppermost row. Altogether our Cambridge 

 specimens agree closely with T. Wiestii, though they are not unlike 

 the T. costatus, figs. 1 & 2 of Sharpe, which appear to me more 

 allied to his T. Wiestii than to the true T. costatus of Lamarck. 

 T. Bergeri, Brong., with its four ranges of tubercles, is also found at 

 Cambridge, but appears to be much rarer than T. Wiestii. 



Helicoceras Bobertianus, D'Orb. 



Helicoceras Bohertianus, Pictet, Traite de Pal. ii. p. 713, pi. 56. 

 f. 10. 



Turrilites Bohertianus, D'Orb. Pal. Fr. p. 585, pi. 142. 



M. Pictet has transferred this species from the genus Turrilites to 

 Helicoceras, in consequence of the whorls being slightly separated. 



