262 Canadian Recard of Science. 



development of the trilobites of the genera Olenellus and 

 Paradoxides (related genera) it will be observed that a long 

 or continuous eyelobe. and one drawn in at the posterior 

 angle of the dorsal suture, is a character of the early forms, 

 both as larval individuals and as these genera exhibit them- 

 selves in successive strata. So well does 0. Zoppii represent 

 an Olenellus or a Paradoxides that if the glabella were con- 

 cealed the rest of the body would meet the requirements of 

 a form combining these two genera. 1 Prof. Meneghini 

 also compares his species to 0. micrurus, one of the oldest 

 species of Olenus of the north of Europe, and the one which 

 there best preserves the Paradoidean type. 



In Olenus armatus, the second species of this genus des- 

 cribed by Meneghini, other primordeal features of the Para- 

 doxides family appear, but chiefly as they show themselves 

 in the genus Olenellus 2 — the glabella strongly lobed and 

 nearly reaching the front of the head shield, and the pro- 

 minent and large rachis, armed with spines, bring it into re- 

 lation with Holmia ; but the pygidium is more distinctly, 

 than in 0. Zoppii, that of an Olenus. 



The remains of species of Paradoxides which have been 

 recovered in Sardinia are too defective for comparison, but 

 so far as can be judged they are those of the Lower Para- 

 doxides beds, rather than those of the Upper. It is some- 

 what strange that no hypostomes of Paradoxides are figured 

 or described by Meneghini. 



A remarkable group of trilobites in this fauna is the 

 Conucephalites with a tubercle in front of the glabella. Of 

 these there are three species, or perhaps one might say four, 

 if 0. Bornemanni be included, in which the tubercle is con- 

 fluent with the front of the glabella. Prof. Meneghini com- 

 pares one of these species with 0. typus, Dames, of the Cam- 



1 In Holmia (Olenellus) Kjervlfi the front of the glabella is small 

 compared with the Paradoxides. See de Undre Paradoxideslagren, 

 Linnarsson, Stockholm, Tafl. III., figs. 12 and 14 ; also Om Skur- 

 ingsroaerker, Kjerulf, Christiania, p. 83, figs. 1,2, 3. 



! Compare Tav. II. , figs. 6 and 7, with figures referred to in the 

 last foot note. 



