86 ROYAL SOCIETY OF CANADA 



pygicliuin diller also from those ascribed to that species by Waleott. It 

 diftors from all the Paradoxides in its conical glabella, as well as in the 

 details of the ornamentation of the surface. Solenopleura (?) Ifarveyi, 

 Waleott, resembles the sjiecies in some respects, but is much smaller, and 

 belongs to a lower horizon (No. 2) of Walcott's section. 



In this species we have a good example of the Sardinian genus 

 Metadoxides, and apparently the most jirimitive example of the genus 

 known, M. torosus, Menegh., has just such a thorax and pygidium, but 

 has evidence of more advanced development in the head-shield ; this is 

 chiefly in the shorter eye-lobe, closer to the glabella, the more spreading 

 course of the posterior extension of the dorsal suture, and the condensa- 

 tion of the head in front of the glabella. The meaning of these ditier- 

 ences is apparent when we study the development of Paradoxides. P. 

 Acadi'cus, for instance, shows a much wider extension of the marginal 

 area of the head-shield in the larval, than in the adult stage. The with- 

 drawal of the eye-lobe from the vicinity of the margin toward the 

 glabella, is seen to be one of the progressive changes that occurred dur- 

 ing the growth of the Ptychoparina> of the Paradoxides Beds at St. John. 

 The short posterior extension of the dorsal suture is an almost universal 

 characteristic of the trilobites of the Protolenus Fauna. Here, then, are 

 three criteria from which we may infer the Newfoundland species to be 

 an older (or at least a more primitive) type of Metadoxides than those of 

 Sardinia. 



Another species of Sardinian Metadoxides ( Jf. Bornemanni) does not 

 show such primitive characters as M. torosus, for not only is the whole 

 head more compact, but the condensed pygidium with its costate side 

 lobes, introduces a feature, quite at variance Avith the usual appearance 

 of the pygidium in Paradoxides, and more like that in Conocoryphe ; if 

 this species may be retained with M. torosus in Metadoxides, there is 

 greater reason for referring to this genus the new species from New- 

 foundland. 



(Quotation from Bulletin No. xvii., 1899, of the Natural History 

 Society of New Brunswick, in reference to Metadoxides. 



Since writing the above, it has seemed to the author desirable to 

 make a broader distinction between the Sardinian and American species 

 of Metadoxides than that given above. He has heretofore depended 

 upon the view of the Sardinian succession given by Barrande and Mene- 

 ghini, from which one may infer the presence of two Cambrian lauiias in 

 Sardinia, the lower containing Olenop^s, Metadoxides, Paradoxides, etc., 

 and the upper Criordanella (Asaphus, Menegh.) Neseuretus, etc. 



Bornemann, however, seems to throw doubt upon the entire separate- 

 ness of these faunas, when he says that remains of Giordanella are found 

 with Metadoxides armatus.^ If this is the case it will carry the 



' Versteinerungen des cambrischen Schichtensystem der Insel Sardinien, p. 465, 

 Halle, 1801. 



