156 MESSES. A. J. JUKES-BROWNE AND W. HILL ; [May 1 896, 



Ammonites obtectus, Sharpe, ' Chalk Moll.' p. 20, pi. vii. fig. 4. 



This is another peculiar ammonite described by Sharpe from a 

 single specimen obtained by Mr. Wiest at Chardstock, and is one of 

 the many species which occur at that locality and on the coast. 

 The specimen found by Mr. Meyer came from his Bed 11, Duns- 

 combe, and this and one x from the ' Chalk with many Micrasters' 

 of Dover are, so far as we know, the only others yet discovered. 



Ammonites Renevieri, Sharpe, ' Chalk Moll.' p. 44, pi. xx. fig. 2. 



This is a rare Lower Chalk fossil found in the Isle of Wight and 

 near Devizes, and also obtained by Gueranger in the Cenomanian 

 of Le Mans, so that it is one of the species which links the Devon 

 beds with the Lower Chalk, on the one hand, and with the typical 

 French Cenomanian on the other. Mr. Meyer found it in Bed 13 

 on a large fallen block below Whitlands, near Lyme Regis. 



Ttjrrilites Bechii, Sharpe, ' Chalk Moll.' p. 66, pi. xxvi. fig. 13. 



The original specimen of this was found near Lyme Regis by 

 Sir H. De la Beche. Mr. Meyer has obtained specimens from his 

 Beds 12 and 13 (see list). At present it is known only from, 

 Devon. 



Ammonites (Acanthoceras) pentagontjs, sp. nov. (PI. V. figs. 1 

 & 1 a.) 



This shell has some resemblance in general shape and curvature 

 to the flattened forms of Ammonites Mantelli, but in the number 

 and arrangement of its dorsal tubercles it resembles A. Deverianus, 

 d'Orb. 



Only one specimen has been found, and this is figured in PI. V. 

 figs. 1 & la. Its dimensions are: — longest diameter 4 inches, shortest 

 3 inches ; height of last whorl 1*8 inch, and width of mouth about 

 1-6 inch. 



The whorls are about three parts involute, and the umbilicus is 

 consequently small. The sides are flattened and the back rounded, 

 A certain number of ribs, probably about 18, start from a set of 

 tubercles, which surround the umbilicus, but on the sides other ribs 

 come in, one or sometimes two between each of the first set, all 

 becoming of nearly equal size and passing regularly over the back. 



Each rib bears five equidistant tubercles, three on the back and 

 one on each side of these, where the back curves to meet the sides. 

 Thus, viewed from the back, five rows of tubercles are visible, the 

 median row being the most prominent, and the two outer rows being 

 the least elevated. 



The ribs and tubercles are best developed in the younger part of 

 the shell. In the body-chamber beyond the last sutural line some 

 curious changes take place ; for a space on the sides the ribs almost 

 disappear, then the tubercles on the back become smaller, and near 



1 W. Hill on the Chalk of Dover, Quart. Journ. Geol. Soc. vol. xlii. (1886)- 

 p. 242. 



