26 FAUNA OF THE CORNBRASH. 



perhaps to be correlated with the vertebra mentioned above. Only the distal half 

 is preserved : it has an elliptic cross-section throughout, the axes of which change 

 from 38 mm. X 31 mm. in the centre to 109 mm. X 23 mm. at the distal end. In a 

 transverse direction the distal outline is uniformly curved with a sagitta of 24 mm. 

 (in 109). The posterior outline being the most curved, the greatest thickness is 

 nearer the anterior side. 



Specimens such as this are of comparatively little value by themselves palseon- 

 tologically, but they are of great interest as showing that the Reptilia of the 

 Cornbrash mainly belonged to the great marine family that frequented the 

 Oxfordian seas. 



Order GBOGODILIA. 



Family Teleosaurid.e. 



Genus MACHIMOSAURUS, v. Meyer. 



This genus is denned by its author (' Neues Jahrb.,' 1837, p. 560, where it is 

 misprinted "Machimosaurus," an error corrected in 1838, p. 415) as "a saurian 

 with strong, obtusely conical, and closely striped teeth," which is insufficient 

 without his reference to Romer (" Ichthyosaurus," ' Verst. N. D. Ool.-gebirges,' 

 p. 12, pi. xii, fig. 19), who describes a tooth as "thimble-shaped, covered with 

 about 100 fine, sharp, close-set longitudinal folds, which are wrinkled at the 

 summit." This defining description is of a specimen from the " Portland Stone," 

 meaning thereby Pterocerian or Virgulian of Kahlenberg, Hanover ; so that the 

 genus is an Upper Jurassic one. 



Machimosaurus rigauxi, Sauvage. Plate I, fig. 5. 



1879. Machimosaurus rigauxi, Sauvage et Lieuard, Mem. Soc. Gcol. France [3], vol. i, 

 no. 4, p. 4. 



SJciatype. — " The teeth have their enamelled portion adorned with fine and 

 close striae, replaced on both faces about the middle of their length by undulating 

 vermiculate lines, following towards the summit, which is, as it were, guilloched, 

 the lines being a little stronger and less crowded than those at the base of the 

 tooth. Between the principal strise at the base are intercalated some which rise to 

 a feeble height. The lateral angles are marked, especially in the upper third of 



