Chalk Fishes 57 



under the name of Saurospondylus dissimilis. There is, how- 

 ever, good ground to believe that they are inseparable from 

 the lizard-like marine reptile known as Dolichosaurus longi- 

 collis, from the Chalk of Kent and elsewhere. 



The following species of fishes have been recorded from the 

 Chalk of the county. The dagger-like teeth of the shark 

 known as Oxyrhina angustid&ns are far from uncommon at 

 Cherry hin ton, and it is probable that remains of Lamna 

 appendiciilata, and perhaps of other kinds of sharks, also 

 occur in the same pits. The large crushing palatal teeth of 

 that common Cretaceous ray Ptychodus decurrens are like- 

 wise met with in the Cambridgeshire Chalk. Among the 

 chimaeroids, the extinct genus Ischyodus is represented in 

 the Sedgwick Museum by one half of the lower jaw of the 

 species known as /. thurmanni, from the Lower Chalk of 

 Isleham, near Newmarket 1 . Passing on to the bony fishes we 

 find that in the extinct family P achy cor midae the well-known 

 Cretaceous fish Protosphyraena ferox (often incorrectly called 

 Saurocephalus lanciformis} is represented by its dagger-like 

 teeth at Cherryhinton, and more rarely by the solid beak-like 

 extremity of the jaw. Among the more herring-like fishes of 

 the family Elopidae we find teeth and jaws of Pachyrhizodus 

 subulidens (formerly regarded as those of a lizard) recorded 

 from Cherryhinton, the Sedgwick Museum possessing one 

 particularly fine lower jaw from that locality 2 . The Lower 

 Chalk of Burwell, near Newmarket, has yielded the type speci- 

 men of the species known as Prionokpis angmtus^ which is a 

 member of the extinct family Enchodontidae, related to the 

 scopeloids and pikes. The type specimen is preserved in 

 the British Museum and its counterpart in the Sedgwick 

 Museum at Cambridge. The species also occurs at Cherry- 

 hinton. To the same family belongs Apateodm striatus, 

 occurring typically in the Chalk at Lewes, but also recorded 

 from that of Cherryhinton 3 . 



1 See Woods' Type Fossils in Woodward. Mus. 163. 2 Ibid. 162. 



3 Smith Woodward, " British Chalk Fishes " (Mon. Pal. Soc. 1902), 41. 



