BV K, ETHERIDGE, .TUNR., AND JOHN MITCHELL. 493 



stone, Parish Bell, County Ashhurnham, wliere it was associated 

 with Broiiteus angiisticaudatus. It appears to be more closelv 

 related to Crotalocejyhalus {Chei?'urus) sterttheryi Boeck, tlian to 

 any otlier known to us, though .there appear to be some differ- 

 ences between it and tliat species, M'hich lead us to defer our 

 determination for the present. For instance, the glabella of C. 

 sternbergi has its greatest width across the frontal lobe; in the 

 present foi-m the greatest glabella-width is across the second lobe. 

 The proportions of the length of the cephalon to the greatest 

 tran.sverse width of the frontal glabel la-lobe, as shown by mea- 

 surements made of two cephala of C. sternhergi figured by 

 Barrande,* are respectively, 21:17, and 27:21mm.; and, for 

 the Molong species, the proportions are, 18:10. These propor- 

 tions of the two widely differ. The ornamentation of tiie fixed 

 cheeks of the Molong specimen is finer and more granulate than 

 that of the free cheeks of C. ste7'7ibergi^ and approaches, in char- 

 acter, nearer to the ornamentation on the similar parts of Ch. 

 insignis Barr. The Molong form, too, seems to have borne short 

 genal spines, resembling those of Ch. iiisigiiis rather than C. 

 sternoergi. The subparallel-sided glabella, fixed cheek ornamenta- 

 tion, narrow frontal glabella-lobe, and the transversely nearly 

 sti-aight course of first and second glabel la-fuiiows serve to 

 separate the Molong from the Bowning forms. 



Genus SPHiEKKXOCHUs Beyrich, 1845. 

 (Ueber Bohmischen Trilobiten, 1845, p. 21,^7^6 Salter). 

 History.— Dr. A. R. C. Selwyn was the first to record the oc- 

 currence of this interesting genus in Australia. Specimens were 

 found by the Geological Survey of Victoria at the junction of 

 Woori-Yallock Creek with the Yarra River. f In New South 

 Wales, Mr. C. Jenkins had the honour of announcing its first 

 discovery. He figured a remarkably good example, presumably 

 from the Yass-Huine beds.! He remarks: '' Tha Sphicrexochus \s 

 almost identical with SplutrexocJius as figured by Murchison." 



* Barrande, Sy.st. Sil. Jioheme. 



t Selw3Mi, Quart. Journ. (4eol. Soc, xiv., ISfiS. p..');iS. 



:;: Jenkins, Pioc. Linn. Sue. N. S. Wales, iii., Ft. 1, 187S, pp.2H-27, Pl.«),Hir.'2, 



