PURBECK LIZARDS. 657 



Moreover, the geological deposit (a subdivision of the Parbeck series) containing the grani- 

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

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

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

 the more regular ' lay,' or disposition, of the ' lacunas ' 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 lacunae, 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. 



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



