Cambrian Faunas. 259 



ness of slates, and to contain only one species of Para- 

 doxides (P. rugulosus, Corda. var.) The species here attains 

 an unusually great size, and, as M. Bergeron remarks, com- 

 pares for size (being about a foot in length) with the great 

 Paradoxides of other countries. Being so large and occu- 

 pying the field for so long a period, we may believe that 

 the conditions which surrounded it were highly favour- 

 able to its growth and development, and that the south of 

 Europe may have been one of its principal centres of dis- 

 persion. 1 



The variety of P. rugulosus, found at Montaigne Noire, is 

 remarkable for the prolonged points of the side lobes of the 

 pygidium. In this respect it departs from the type of the 

 species found in Bohemia, and from. P. Eteminicus found in 

 Acadia. 2 



That this fauna is parallel to that of Division 1 c. 2 of 

 the St. John group is clear from the following comparison 

 of species : — 



1 Although the writer has stated in a previous publication that 

 P. rugulosus in Scandinavia was preceded by P. tessini, an exami- 

 nation of the characters of one of the forms which Dr. Brogger 

 has referred to this species (as a variety) seems to show that it is 

 a distinct species. Dr. Brogger speaks of two varieties occurring 

 at Krekling, Norway; a large form with smooth shield: and a 

 smaller one with finely granulated shield ; neither variety of surface 

 is that of P. rugulosus, and the large form differs also from the 

 type of this species in the shape of the glabella, as well as in the 

 form of the hypostome (to which the doubleur is attached) ; and 

 in these respects also from P. Eteminicus, the Acadian represen- 

 tative of this species. The small form approaches much closer 

 to the type P. rugulosus, and may be of that species. 



2 It approaches in this respect, as well as in its long eyelobe, the 

 genus Centropleura of Angelin, of which genus Angelin made P. 

 Loveni, found at a higher horizon, the type, and in which he in- 

 cluded C. decrieurus (Ang.) and C. serratus (S. & B.) of a still higher 

 horizon ; but Centropleura Loveni has four points to the pygidium, 

 and belongs to the same group of Paradoxidean forms as the Welsh 

 Anopoleni. The two other species of Centropleura named above 

 are referred by the latter Swedish geologists to Dicellocephalus. 



