380 



Loc. — Forty miles south-east of Elkedra Cattle Station 

 (deserted), about 150. miles south of Alexandria Cattle Sta- 

 tion, Barkly Tableland. 



Hot. — Cambrian (Etheridge). 



Agnostus australiensis, Chapman. 



(?) Agnostus, sp., Chapman: Proc. Rov. Soc. Vict., xxi. 

 (n.s.), pt. i., 1908, p. 268. 



Agnostus australiensis, Chapman: Ibid, xxiii. (n.s.), pt. ii., 

 1911, p. 314, pi. lviii., figs! 9, 11, 12. 



Obs. — The pygidium in this species differs from that of 

 A. elkedraensis in the presence of the incipient spines at the 

 posterior angles, and apparently by the absence of tubercles on 

 the two lobes of the glabella. 



Loc. — Dolodrook River, Mount Wellington District, 

 Gippsland, Victoria. 



Hot. — Agnostus zone, Upper Cambrian (Chapman). 



Genus Microdiscus, Salter, 1864 ( 33) 

 (Quart. Jour. Geol. Soc., xx., 1864, p. 237). 



Obs. — The name Microdiscus has a strange history as 

 related by Mr. C. D. "VValcott, and may have to give way to 

 that of Pemphigaspis : — "If Pemphigaspis bullatus proves 

 to belong to the same group [as Microdiscus^ . all 



the species now referred to Microdiscus would then be replaced 

 by Pemphigaspis, as Emmon's original name of Microdiscus 

 would not be retained, as it appears to have been founded on 

 a specimen of the genus Trinucleus. ,> ( 34 ^ 



Whilst the name Microdiscus is retained it must be 

 ascribed to Salter, as explained by Lake.< 55 ^ 



Only one species of this strange little genus has so far 

 been discovered in Australian rocks. 



Microdiscus significans, Eth. fil. 



M. significans, Eth. fil.: Off. Contrib. Pal.'s. Austr., No. 13 

 (S. Austr. Pari. Papers), 1902, p. 3, pi. ii., figs. 5-9. 



Obs. — I am not in possession of any additional inform- 

 ation relating to M. sigmficans, which appears to be a member 

 of the M. dawsoni-puctatus group, or those forms possessing 

 a well-marked backwardly-directed cervical spine and multi- 

 segmented pygidium. 



I have re-examined the type specimens in the light of 

 Mr. Walcott's genus Pagetia, but I failed to find any trace 

 of either "eye line" (pelpebral ridge) or eyes. 



(33) Emended : "Walcott. 1886; non Microdiscus. Emmons. 



(34) Wialcott' : Bull. U.S. Geol. Survey, No. 30, 1886, p. 154. 



(35) Lake : Mon. Brit. Cambrian Trilobites, pt. ii., 1907, p. 30. 



