130 Royal Society : — 



like the latter plant, it has a Lepidostrobus for its fructification. The 

 outer cylinder in large Sigillarice is composed of thick-walled quadran- 

 gular tubes or utricles arranged in radiating series, and exhibiting 

 every appearance of the tree having been as hard-wooded as Pinites, 

 but as yet no disks or striae have been observed on the walls of the 

 tubes. Stigmaria is now so generally considered to be the root of 

 Sigillaria, that it is scarcely necessary to bring any further proof of 

 this proposition ; but specimens are described which prove by simi- 

 larity of structure that the former is the root of the latter. 



The chief specimens described in the memoir are eight in number, 

 and were found in the lower divisions of the Lancashire and York- 

 shire coal-measures, imbedded in calcareous nodules occurring in 

 seams of coal. 



No. 1, Diploxylon cycadoideum, was from the first- named district, 

 and the same locality as the Trigonocarpon, described by Dr. J. D. 

 Hooker, F.R.S., and the author, in a memoir on the structure of 

 certain limestone nodules enclosed in seams of bituminous coal, with 

 a description of some Trigonocarpons contained therein*; and the 

 other seven {Sigillaria vascularis) were from the same seam of coal 

 in the lower coal-measures in which the specimens described in a paper 

 entitled " On some Fossil Plants showing Structure from the Lower 

 Coal-measures of Lancashire "f, were met with, but from a different 

 locality in Yorkshire. 



*' On the Fossil Mammals of Australia. — Part II. Description of 

 an almost entire Skull of Thylacoleo carnifex, Ow." By Professor 

 Owen, F.R.S. &c. 



In this Part the author gives additional cranial and dental charac- 

 ters of the extinct marsupial carnivore, Thylacoleo, deduced from 

 examination of better-preserved fossils, obtained from freshwater 

 deposits in Darling Downs, Queensland, Austraha. 



The fore part of the skull, wanting in the first-described specimen 

 from similar deposits in the province of Victoria, is preserved in 

 the present specimen, showing the premaxillary bones, which are 

 relatively larger than in placental felines. Each bone has three 

 teeth, of which the foremost is developed into a tusk, the second 

 and third being very small. There is no canine, or no tooth de- 

 veloped as a laniary in the maxillary bone. In the short extent 

 of the alveolar border of this bone between the great carnassial 

 molar and the maxillo-premaxillary suture, there are two approximate 

 small round sockets, which lodged either one double-rooted tooth or 

 two small single-rooted teeth. But dental development has mainly 

 expended itself upon the perfection of a pair of laniary incisor tusks, 

 in both upper and lower jaws, for piercing, tearing, and holding, and 

 a pair of carnassials in both jaws for flesh-cutting. These, in the 

 present specimen, closely agreed with those described in the former 

 one, but were more worn : they are the largest examples of these 



* Philosophical Transactions, 1855, p. 149. 



t Quarterly Journal of the Geological Society of London for May 1862. 



