6Y R. ETHEIilDGK, .tUNR., AND loHN MITCHELL. 503 



all the ribs are gently convex, but vanish before the margin is 

 reached, thus forming a well-defined border. 



Obs. — This pygidium is clearly separable from all other similar 

 portions of Hrontei, except Chapman's Brontens {Goldius) cress- 

 we/Ji* but this belongs to a different type — tuberculate. Its 

 narrow and elongate shape makes it quite singular. 



We are indebted to Mr. C. Siissmilch for the privilege of 

 describing this species. 



Loc. and //or. — Oaky Creek, Parish Barton, County Asliburn- 

 ham (Siissmilch). (?)Upper ^Silurian. 



Genus Lichas Dalman, 1826. 

 (Kongl. Vet. Akad. Handl. Stockholm, 1826, p.278.) 



History. — Hitherto Lichas has been represented in Australia 

 by two well-marked species — L. australis McCoy, and L. pahnata 

 var. sinuata Ratte, to which may be added an indicated species 

 by de Koninck. 



The first of these was described by Sir F. McCoy in 1876, 

 from specimens from the Upper Silurian rocks at the junction 

 of the Woori-Yallock Creek and Yarra River. Mr. Rattes 

 trilobite, originally figured as L. sinuata, is of great interest 

 from its locality. Ratte remarked on its close relation to the 

 Bohemian L. palmata Barr., and, in a subsequent paper, adopted 

 Barrande's specific name, adding his own in a varietal sense. 



De Koninck's Lichas, fi'om Rock Flat Creek, which takes its 

 place as the second reference in chronological order, was too 

 imperfect for determination, but on account of the irregularity 

 of its general sculpture, he also called attention to Z. palmata. 

 One of us recorded, in error, the occurrence of Lichas from the 

 Bowning area {loc. cit., ante). 



Mr. F. Chapman records L. au^tralis in his list of Victorian 

 Trilobites.t 



Section Acanthopygk Corda, 1847. 

 (Prod. Mon. Bohmischen Trilobiten. 1847, p. 144). 



One segmental lobe on each side of the glabella. 



* Chapman, Proc. Roy. 8oc. Vict., xxviii. (N.S.), Pt.l, 1915, p. 160, PI. 

 16, tig. 17. 



' t Cliiipmau, llepoit Austr. Assoc. Adv. 8ci., xiv., lOlo, p. 229. 



