WEALDEN FORMATIONS. 17 



In fig. 18, PI. II, is represented a ' granicone ' with a basal breadth of 8 mm., and a 

 length or height of cone of 14 mm. In Eig. 19 the base is oblique, reducing the shortest 

 side of the cone to a height of 8 mm. In this, as in some of the similarly shaped 

 ' granicones,' part of the basal margin is raised or prominent, sometimes formed by a single 

 series of close-set granules, as in Eig. 20. Those on the surface of the cone are less 

 regularly disposed, but at some parts affect a longitudinal arrangement (Eig. 21.) The 

 apex shows various degrees of obtuseness, which finally reduces the granulate or exterior 

 surface of the cone to a moderate convexity, but the conical shape is the rule. The 

 smallest of such ' grani-cones ' has. a basal breadth of 3 mm., a length of 5 mm. 



Slices of these enigmatical fossils prepared for the microscope demonstrated the 

 absence of the structures characteristic of piscine dermal bony cones and spines. Moreover, 

 the geological deposit (a subdivision of the Purbeck series) containing the granicones is 

 a fresh-water one, and their structure was equally distinct from the ganoid dermal 

 defences of the Sturionidcs or other fishes habitually frequenting lakes or rivers. The 

 dermal scutes of Theriosuchm are notable for the greater number of the canaliculi, and 

 the more regular ' lay,' or disposition, of the ' lacunae ' or bone cells, than in Lacertians ; 

 also by the wider ' sinuses ' or unossified tracts. In the dimensions, size, shape, and 

 number of the ' canaliculi ; ' in the minor regularity of the ' lay ' of the lacunas, and in 

 the less proportion in both number and dimensions of the sinuses, the bony tissue of the 

 granicones resembled that in Lacertians ; and in this conclusion from microscopical 

 characters,^ combined with the evidence of the association, and the contiguity of the 

 granicones, with the unquestionable fossil remains of Nuthetes destructor, I derive the 

 grounds for referring them to that extinct genus and species. 



Among modern Lizards the singular ' Moloch horridus ' of Australia exemplifies 

 dermal scutes most nearly resembling these ' granicones ' in shape ; but the horny 

 exterior is supported by dense fibrous tissue, not bone. It may be that we have in them 

 a formal exemplification of the dermal armour of Nuthetes destructor. If so, the 

 association of a Lizard of such forbidding physiognomy with small Marsupials having 

 their nearest of kin in Australia would be worthy of note. 



At the conclusion of my former Monograph on Mesozoic (Wealden and Purbeck) 

 Crocodilia, allusion was made to the differences they presented in characters of the bony 

 palate, extent of attachment of mandibular muscles, vertebral articulations, and dermal 

 armature, from the Neozoic Crocodilia ; differences which suggested the relation of such 

 modifications in the Tertiary and existing Crocodiles and Alligators to freer or more 

 frequent life on dry land, and greater power of grappling with and drowning large 

 terrestrial mammals. 



One of these reptiles having seized and submerged a tiger or buffalo, admits the 

 water into its wide, unlabiate mouth, by the spaces to which the thickness of the part of the 

 prey gripped keeps asunder the upper and the lower jaws. Thus, the part of the mouth 

 ^ See 'Journal of the Royal Microscopical Society,' vol. i, No. 5, p. 233, pis. xii and xiii. 



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