60 Mr. Lydekker. On the Generic [Dec. 18 r 



assumption of the accuracy of the c-formula, and have not been 

 directly referred to the air thermometer. We believe, however, that 

 they are probably correct to 0'l C., and that they may be safely used 

 to standardise thermometers of limited range, in cases where it may 

 happen to be inconvenient to make use of the sulphur point. 



In comparing the platinum and air thermometers between and 

 100 C. observations were taken at intervals of 5 all the way up. 

 The mean deviation of the observations from the parabolic formula 

 (d) is only 0"'006. This corresponds to the limit of accuracy of the 

 barometric readings, and there is no reason to suppose that the 

 ^-formula may not represent the difference even more closely than 

 this. 



The same platinum thermometer has been compared with several 

 mercury thermometers standardised at Kew.* The result seems to 

 show that the Kew standard reads 0'l C. lower than our air-ther- 

 mometer at 30. 



II. ft On the Generic Identity of Sceparnodon and Phaxcolonus" 

 By R. LYDBKKER, B.A. Communicated by Professor W. H. 

 FLOWER, C.B., F.R.S. Received November 19, !!<>. 



[PLATE 1.] 



In the year 1872, Sir Richard Owen described and figured in the 

 ' Phil. Trans.'f two imperfect lower jaws of a large extinct Wombat, 

 from the Pleistocene of Queensland, under the name of PJiascolomys 

 (Phoscolonus) gigas, the term Phascolonus being employed in a sub- 

 generic sense. The species Phascolomys gigas, it should be observed, 

 was founded by the same writer J at an earlier date, upon the evidence 

 of a detached cheek-tooth. Subsequently Sir Richard 0\veu de- 

 scribed and figured certain imperfect upper incisors, from Queensland 

 and South Australia, characterised by their peculiarly flattened and 

 chisel-like shape, under the new generic name Sceparnodon, which 

 was suggested from their contour. 



In cataloguing the fossil Mammalia in the collection of the British 

 Museum, || I was at once struck by the circumstance that, while the 

 upper incisors of the so-called Phascolomys gigas were unknown, there 

 were no cheek-teeth which could be referred to Sceparnodon, and it 

 accordingly occurred to me that the two might prove to be identical. 

 Support was afforded to this conjecture by the following circumstances : 

 1st. The incisors of Sceparnodon agreed fairly well in relative size 



Griffiths, ' Brit. ASBOC. Report,' 1890. 



f Page 257, PI. 3638, 40. 



J Encyclopaedia Britannica,' 8th ed., TO!. 17, p. 175 (1859). 



' Phil. Trims.,' 1884, p. 245, PI. 12. 



j| ' Cat, FOBS. Mamm. Brit. Mus.,' pt. 5, pp. 157159 (1887). 



