24 NEW YORK STATE MUSEUM 



the former species also the pygidium has the axial row of tubercles 

 smaller and duplicate toward the extremity, and lacks the fine granulation 

 of the entire surface. 



The species is not iincomraon in this fauna. 



Cordania hudsonica sp. nov 



Plate 2, ag. 17, 18 



A few pygidia show the presence of a quite distinct species of this 

 genus. They are of small size, broad and quite short, the axis covering 

 about one third the width of the shield, somewhat flattened and not 

 incurved as in Cord, becraftensis and Cord, cyclurus. They 

 bear eight or nine narrow, transverse annulations which show no angu- 

 lations. The pleural ribs are six, with a trace of a seventh, are quite 

 narrow, with interannular furrows of equal width. They are divided by 

 quite deep sulci, and the surface carries a few scattered tubercles. 



Cyphaspis minuscula Hall (sp.) 



Plate 2, flg. 21, 25 



1888. Cyphaspis minuscula Hall and Clarke, Paleontology of New York. 7 : 140, 



pi. 20, fig. 17; 24, fig. 7-12 

 1892. Cyphaspis sp. nov., Clarke, op. cit. p. 412 



Cranidia of this species, distinguished from the closely allied Cyph- 

 aspis coelebs H. and C. of the Helderbergian by the low median 

 angulation of the glabella, are not of infrequent occurrence. Pygidia 

 referable to the species have also been observed. 



Cyphaspis minuscula is quite widely distributed in the 

 Onondaga limestone of New York, and our present knowledge leads to 

 the belief that it may not be easy to fix on a genuine specific difference 

 between it and the Helderbergian form. The latter is exceedingly rare, 

 and but two very imsatisfactory specimens have been seen. The feature 

 above cited is the only one which could now be indicated as distinctive. 

 Both however are sufiiciently unlike the other Devonic species of the 

 genus, and represent a type characterized by the absence of any peculiar 

 arrangement of tubercles, spines or punctae on the surface, the exterior 

 being smooth or very finely granular. 



