414 PETRIFACTIONS AND THEIR TEACHINGS. CHAP. V. 



palaeozoic formations. M. Agassiz has divided them into 

 genera, according to their form and sculpturing. 



This Case contains some beautiful Ichthyodorulites from 

 the Chalk, Oolite, Lias, and Devonian strata, of the genera 

 Oracanthus, Ctenacanthus, Asteracanthus, Gyracanthus, Lepta- 

 canthus, Ptychacanthus, &c. 



4. [2.] Teeth offfybodus, and maxillary bones of Chimceroid 

 fishes : a fine series of the latter. Some of these beautiful speci- 

 mens were collected by the late FREDERICK DIXON, ESQ. from 

 the London Clay, at Bracklesham, Sussex, namely, Eda- 

 phodon, Ischyodus, &c. which have been figured and described 

 by Sir Philip Egerton. 1 



The other division of this Case is devoted to teeth of the 

 Squalidce, or Shark family; many are fromj the Sussex 

 Chalk, and belong to the genera Lamna, Otodus, Notidanus, 

 &c. There are also spines of a species of Acanthias, from the 

 Lower Chalk, &c. 



6. [3.] Vertebrae, teeth, and spines of Squalidse from the 

 Chalk, &c. Teeth and other remains of Hybodus from the 

 Wealden, Oolite, and Lias. 



8. [4.] Teeth of fishes allied to the Cestracions. The Cestra- 

 cion is a genus of existing fishes inhabiting the seas of New 

 Holland, and is commonly called the Port- Jackson Shark. 



Teeth of species of Ptychodus (generally known as fossil 

 palates, leeches, &c.), from the Chalk ; and of Acrodus, Oro- 

 dus, Cochleodus, Psammodus, Strophodus, Ctenoptychius, &c. 



10. [5.] Teeth, and maxillary bones of fishes of the Ray 

 family, chiefly from the London Clay. Many are from Brack- 

 lesham, and were collected by the late Mr. Dixon. They 

 comprise specimens of Myliobates (Mul-rays), and JEtobates, 

 (Eagle-rays), &c. 



In the other compartment there are portions of the bony 

 proboscis and teeth of the Pristis or Saw-fish, which are of 

 extreme rarity in a fossil state. There are remains of two 

 extinct species ; Pristis Hastingsice and P. distortus, from 

 Bracklesham, and Hordwell, &c. 



In this Case there is a slab of limestone from Solenhofen, 

 with numerous articulated rays of the dorsal fin of a large 

 fish, presented by the late Marquis of Northampton. 



1 In the late Mr. Dixon's " Fossils from the Cretaceous and Tertiary 

 Formations of Sussex," 1 vol. 4to. with numerous beautiful plates. 

 1851. 



