EARLY DEVONIC HISTORY OF NEW YORK AND EASTERN NORTH AJIERICA 1 9 



Proetus sp. 



Plate 1, figures 4-6 



There are two species of this genus present : 



1 A small form of the type of P. phocion Billings and P. con- 

 radi Hall, widespread throughout early Devonic formations; in which 

 the glabella is conate, broad, obscurely lobed, the anterior margin of the 

 cranidium ilat and narrow, the pygidium small with a broad and short 

 spindle having 7 annulations, narrow pleurae with 4 or 5 duplicate ribs and 

 a thickened border. 



Horizon. No. 9. 



2 A much larger form represented by a long pygidium with narrow 

 axis having 7 or 8 annulations and relatively broad pleurae with 5 or 6 

 duplicate ribs. 



Horizon. No. 8. 



Beyrichia kloedeni McCoy cf. var. acadica Jones 



See B ey ri c h i a kloedeni McCoy var. acadica Jones. Ann. & Mag. 1889. Ser. 

 6, 3:379. Pi- T 7. fig. 3" 6 - 8 > 9 



Professor Jones figures 6 specimens, described from Stewart's cove, 1 

 these "being referred to B. kloedeni as so many subvarietal individuals 

 falling into one varietal group." The true B. kloedeni itself exhibits 

 a considerable variety of lobes and furrows. The Gaspe specimens in the 

 form of their posterior and frontal lobes, the isolation and round shape of 

 the middle lobe and in their dimensions present individual similarities with 

 those from Dalhousie. The middle lobe is on the whole a little shorter 

 than in the largest from that locality, well isolated and the confluence of 

 the large lobes is more complete. The species is not unlike B. no tat a 

 ventricosa Hall from the Helderbergian though the latter has a 

 narrower anterior lobe. 



The specimens attain a length of 4 mm, a width of 2.5 mm and a 

 hight of .9 mm. Specimens of but 1 mm in length, which evidently repre- 

 sent the young of the variety under consideration, differ markedly from the 

 mature examples in the absence of one or both of the sulci bounding the 

 middle lobe, the latter only appearing as a low prominence upon the even 

 surface of the valve, and in the complete absence of the median ventral 

 depression separating the two large lobes. This approach of young forms 

 to the aspect of Primitia has been observed in the young of Beyrichiae by 

 Verworn and Walcott. 



Horizon. No. 12. 



'Termed in the original description, Cape Bon Ami. 



