306 Mr. H. G. Seeley on Acanthopholis platypus, 



Acanthopholis is a genus of Pachypod animals instituted by 

 Professor Huxley, in the ' Geological Magazine' for 1867, for 

 a Scelidosaurian from the chalk-marl of Folkestone — Scelido- 

 saurian rather than Dinosaurian, because the three families 

 typified by Scelidosaurus, Iguanodon^ and Megalosaurus seem 

 to show affinities so various as to make it doubtful whether 

 Scelidosaurus can be included in the same order with the 

 Megalosaurs. 



The genus has occurred sjjaringly for the last ten years in 

 the Cambridge Upper Greensand, but is rarely represented by 

 any parts except foot-bones, caudal and dorsal vertebrae, 

 and scutes. These fossils indicate, by the difference in the 

 form of the bones, three species, which varied in size from 

 that of a sheep to that of a small ox. They had the tail 

 shorter and smaller than is usual with Iguanodonts, were 

 heavily striped with dermal armour, had large limbs, which 

 do not appear to have been so unequal or so long as among 

 the Iguanodonts ; and the animal had not a large head. 



To the largest species I have given the name AcanthoplioUs 

 platypus ; but, like too many of the osseous relics of the Cam- 

 bridge Greensand, the remains indicate but a small portion of 

 the animal — in this case the metatarsal bones of one foot, a 

 worn phalange, and six caudal vertebrae. And it is right to 

 remark that the association of these bones as remains of one 

 individual rests on no other evidence than their having been 

 disinterred together in the same pit (at Bottisham), and no 

 other remains of a like kind having occm'red near them. And, 

 after study of the specimens and comparison of them with 

 other remains of Acanthopholis^ I see no reason to doubt the 

 association being natural ; and they make known a form of 

 foot-bones and vertebrae of which no other example is known. 

 No materials are available for judging whether this species is 

 identical with or distinct from Prof. Huxley's type species, 

 A. horridus^ since no teeth have come under my notice which 

 can be referred to the genus and compared with the premolar 

 or incisor teeth figured by Prof. Huxley ; and the scutes which 

 that gentleman figures, and the vertebrge described in his me- 

 moir, are remains which afford no data for specific comparison. 

 I may here express a conviction that in dealing with fossil 

 remains of large animals, the anxiety of naturalists to allow 

 every possible margin of variability to their species ratlier 

 than risk the creation of a doubtful type, has led, with some 

 orders and among Eui'opeans, to the retaining of groups of 

 Linnean magnitude, where the species are really genera ; and 

 thus false conclusions result as to the want of stability of 

 character in extinct types, as to the fewness of genera, and 



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