NO. 5 CAMBRIAN TRILOBITES 385 



those species or of ^. iddingsi. It also has lo segments in the thorax . 

 and the related species have nine. 



The largest pygidium in the collection has a length of 15 mm., 

 which indicates a length of 50 mm. for the dorsal shield to which it 

 belonged. 



Formation and locality. — Middle Cambrian: (4g) Wolsey shale; 

 5 miles (8 km.) east-northeast of Logan and i mile (1.6 km.) north 

 of junction of East and West Gallatin Rivers [Three Forks sheet 

 (U. S. G. S.)], Gallatin County, Montana. 



ASAPHISCUS(?)CAPELLA, new species 



Plate 59, figs. 2, 2a-c 



The cephalon and thorax of this species are much like the same 

 parts in A. wheeleri except that ^. ( f) capella has genal spines on the 

 free cheeks and a more distinctly concave frontal border. Its py- 

 gidium differs decidedly from that of A. zvheeleri in having a very 

 wide, sloping, and slightly concave border section and doublure, that 

 terminates within a narrow border; a tapering axial lobe that is 

 three-fifths the length of the pygidium is extended across the wide 

 lower slope as a low, rounded ridge that expands towards the posterior 

 margin and merges into it ; the seven rings on the axis extend out- 

 ward and backward across the pleural lobes as slightly rounded, 

 nearly flat segments, that terminate by merging into the narrow 

 border. 



The largest dorsal shield has a length of 56 mm., and nine thoracic 

 segments, and a small node at the center of each segment and the 

 occipital ring. 



The pygidium, large eyes, and terminations of thoracic segments 

 suggest a different generic reference, but I am not prepared to make 

 it at present. 



Formation and locality. — Middle Cambrian: (54Z) Wolsey shale; 

 Half Moon Pass, Big Snowy Mountains, Fergus County, Montana. 



ASAPHISCUS ? GRANULATUS, new species 



Plate 61, figs. 2, 2a 



This species differs from A. f minor in having 10 thoracic seg- 

 ments, a strong median spine on the axial lobe of the ninth segment, 

 and in its granulated surface. The surface of the test is minutely 

 granular with large granules scattered over the cephalon and a row 



