522 



MONODON. 



This specimen was purchased at the sale of Mr. Park- 

 inson's collection by the Earl of Enniskillen, who most 

 kindly transmitted it to me to have the figures taken 

 from it which are placed at the head of the present sec- 

 tion. The specimen has lost much of the original animal 

 matter, is absorbent, rather friable, and partially decom- 

 posed, so that the layers of the basal substance of the 

 dentine might be easily separated. In what length of time, 

 simple exposure to the elements on the sea-shore would 

 produce this state of decomposition, I know not ; but 

 I have only witnessed such a state in fossils of the age 

 of the post-pliocene extinct Mammals. 



The fragment above figured is the basal part of the tusk ; 

 it measures ten inches and a half in length, and nine inches 

 in circumference: fig. 215, 2 , shows the short and wide 

 conical pulp-cavity at the inserted end, and fig. 215, 3 , 

 the opposite fractured end, where the pulp-cavity begins 

 again to expand as it extends into the exserted part of 

 the tusk. The superficial spiral ridges precisely resemble 

 those at the same heavy implanted part of the tusk in 

 the recent Narwhal. 



A portion of a fossilized tusk of a Narwhal is preserved 

 in the museum of Comparative Anatomy in University 

 College, and is said to have been obtained from the London 

 clay in the neighbourhood of the metropolis.* A portion 

 of the skull of a Monodon monoceros is said to have been 

 found in the marine silt of the marshy plain called Lewes 

 Levels. 



Cuvier mentions a fragment of the Narwhal's tusk, 

 considerably altered in texture, which is preserved in the 

 museum of Natural History at Lyons, and cites a notice 

 of similar fossils found in Siberia. 



* Professor Grant, in Thomson's British Annual, 1839, p. 269. 



