[MATTHEW 1 STUDIES ON CAMBRIAN FAUNAS 87 



Sardinian Cambrian fauna, as a whole, to a higher plane, and imply the 

 separation of these by a wider space of time from the Newfoundland 

 species described above. We think however there are two faunas, with 

 possibly sub- faunas included, 



Meneghini's view would admit of the following arrangement of the 

 Sardinian as compared with the Atlantic North American Cambrian 

 faunas : 



ATLANTIC NORTH AMERICA. SARDINIA. 



XT r Dictyonema Fauna. Giordanella Fauna. 



^PP''' \ Peltura Fauna. 

 Cambrian. \ oienus Fauna. 



Olenopsis Fauna. 

 r Paradoxides Fauna. 

 Lower J The Newfoundland ) 



Cambrian. { Metadoxides. ' 



L Protolenus Fauna. 



In this view the lower fauna of Sardinia might be regarded as inter- 

 mediate homotaxically, between the Paradoxides and Oienus faunas. 

 It is therefore desirable to emphasize the points in which the Newfound- 

 land species differs from the later, and supposed derived forms of Meta- 

 doxides, found in Sardinia, and apply to them sub-generic names, begin- 

 ning with the most primitive. 



1. Species having a widely expanded front to the cephalic shield ; somewhat 

 prolonged eye-lobes ; short posterior extension of the dorsal suture. No costae on 

 the side lobes of the pygidium. Catadoxides n. subgen. Example C. magnificus. 



2. Species having a compacted front to the cephalic shield, short eye-lobes, pro- 

 longed posterior extension of the dorsal suture. 



a. No costa? on the side lobes of the pygidium. Metadoxides, sens, strict.— 

 Ex. M. torosus. 



b. One or more pairs of costa? on the side lobes of the pygidium. Anadoxides 

 n. subgen. Ex. A. armatus, A. Bornemanni (A. arenosus ?) 



co:kocoryphi^^.^ 



Zittel placed this group under Salter's family Conocephalidœ, which 

 is described as having eyes, and therein retains it under Barrande's hetero- 

 geneous genus Conocephalites. which the latter author described as having 

 eyes in the middle of the cheeks, or sometimes having no eyes. The pres- 

 ence or absence of eyes indicating as it does a radical difference of habit and 

 function, is quite overlooked in thus associating together widely diverse 

 species. The absence of the eyes seems to the author sufficient cause 

 without any other to separate this group from Conocephalidse, 



It is more in accordance with its natural relations to place this group 

 of species under Angelin's family Arraphidœ based upon the genera 

 Arraphus ' Harpes, Harpides, etc. ; for to these it is more distinctly 



1 See Trans. Roy. Soc. Can., vol. ii., p. 102, vol. iv., p. 149, vol. v., pp. 121, 163. 



2 Arraphus is suspiciously like a Harpes which has been deprived of the flattened 

 margin, and thus seems an unfortunate choice as the type of a family. 



