70 C/iapnian and Pritcltard : 



the basal grooves. On the other hand, there is evidence of the 

 presence of an anterior ridge sucli as is seen on tlie spines of I), 

 blochii. Both the above-mentioned sjDecies are living in Port 

 Phillip, D. hystrix being readily distinguished by its short 

 spine with a broad base, whilst D. blochii has fewer and more 

 slender spines with a comparajtively narrow base. 



The section of the fossil spine is subtrigonal, with the inner 

 surface concave at the base, the roots or basal prongs making 

 an angle of about 120 degrees with the main shaft. 



Dimensions. — Length, 6 mm. ; wddth from point to point of 

 the roots, 5 mm. ; thickness at the base of the spine, 2 mm. 



Locality and Horizon. — Point Campbell clays. Lake Con- 

 newarre, near Geelong. — Baloombian (Pritchard Coll.). 



Observations. — No separate spines of Diodou appear to have 

 been recorded in the fossil state except those of the type speci- 

 men of D. erinaceus Agassiz, from the Upper Eocene of Monte 

 Bolca, near Verona. ^ It therefore seems desirable to record the 

 above fossil with a distinctive name, especially since the example 

 was found in beds of older date than those from which the 

 palates have hitherto been procured. 



1 Poiss. Foss., vol. ii., pt. ii., p. 271. See also Smith Woodward, Cat. Koss. Fishes, 

 Brit. Mus., pt. iv., 1901, p. 572. 



