Tlte Heatlicotian. 155 



•groove. The fixed cheeks are triangular, long, regularly tapering 

 to the front ; they are gently convex. Neck furrow deep and 

 straight. Thoracic segments large ; the number is probably 

 small. The pleura are wide, but short. 



Type species, Dinesiis ida. R. Eth. ill. : Cambrian Fauna in 

 Victoria. Proc. R. Soc. Vict., Vol. VIII. (new ser.), 1896., 

 pp. 56-57, pi. 1, fig. 1, 2, 3 and -1, not fig. 5 and 6. 



This genus differs from Asaphns by its large, pai'allel-sided 

 glabellum, small eyes, triangular fixed clieek, and much deeper 

 thoracic segments. 



Genus Notasaphus, n. g.^ 



Diagnosis. — An Asaphid, with glabellum expanded widely in 

 front; it is crossed by deep, well marked neck furrow, with a 

 slight projection on the middle line. Lateral furrows barely 

 recognisable. Fixed cheeks broad behind, and with a well- 

 rounded expansion in front of the deep, well marked eye lobes. 

 Free cheeks large. 



Pygidia large, with three or four large annulations on the 

 •axis. In the front pygidial segments the pleura are wide ; but 

 the hindermost pleura are narrow, and the whole bordered by a 

 •wide doublure with the edge broken into four, five or six pairs of 

 long, projecting spines. Number of thoracic segments unknown. 



Distribution. — Lower ordovician. Victoria. 



Type species, Notasaphus fergusoni, n. sp. (PI. XXVI.) 



Affinities. — The collection may include two species of this 

 genus as the number of spines and width of the doublure on the 

 pygidia vary. The cranidia found all appear to belong to the 

 same species, and one of them was attached to a pygidiuin with 

 five pairs of spines. This genus appears to be an asaphid, as 

 the cephalic shield and pygidium are large and sub-equal, and it 

 no doubt had but a small number of thoracic segments. Only 

 some isolated fragments of the thoracic segments remain. 



The genus differs from the other genera of Asaphidae by its 

 spiny pygidium ; but as a doublure is found in some asaphids 



1 From Greek, VOTIOS- southern. 



