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Contributions to the Palaontology of t fie Isle of Wiy/it. 

 By Thomas Wright, M.D. &c. 



Read 4th May 1852. 



It has been supposed that the tertiary beds of England, when 

 compared with those of the continent of Europe, are deficient in 

 mammalian remains ; this opinion, like many other hasty gene- 

 ralizations, if it be not entirely fallacious, requires modification. 

 The valuable series of mammalian remains obtained from time 

 to time from the lacustrine strata of Kyson, Hordwell, and. the 

 Isle of Wight, lead us to believe that if similar facilities existed 

 in these localities for working the beds from whence mammalian 

 bones and teeth are obtained, as is the case in the neighbour- 

 hood of Paris, the richness of the English tertiaries in these re- 

 mains would no longer be a doubtful question. We have been 

 led to this conclusion from facts which have come under our 

 observation during the two consecutive summers we were en- 

 gaged in drawing up a description of the coast sections of Hamp- 

 shire and the Isle of Wight, and which have already appeared in 

 the pages of our Proceedings. Until last summer no remains of 

 the new genus Dichodon had been found, except in one spot in the 

 Hordwell section, when T had the good fortune to discover, near 

 Alum Point, Isle of Wight, a portion of the lower jaw of this 

 singular genus with the true molars " in situ " in beautiful 

 preservation. This jaw fortunately supplies some points in the 

 anatomy of this rare mammal, which were absent in the only 

 specimen hitherto found, and which it is the object of this note 

 to furnish. 



Dichodon cuspidatus, Owen. 



The dental formula of the lower jaw of Dichodon cuspidatus, 

 according to Professor Owen, consists of three incisors, one ca- 

 nine, four premolars, and three true molars, arranged in a con- 

 tinuous series in each ramus, and it is inferred that these were 

 opposed by the same number of teeth in the upper jaw. " There 

 are wanting therefore to establish ex visu the entire dental series, 

 only the first and second premolars of the upper jaw and the last 

 true molar of the lower jaw, the germ of which had not been 

 sufficiently calcified at the time of the animal's death to yield 

 satisfactory evidence of its true form*." Having recently dis* 



* Quart. Jouni C. vol. iv. p. I-' 



