28 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. IO3 



Secret Canyon shale; (loc. 61) south of Hamhurg Mine, Eureka 

 District, Nevada. 



Holotype.— U.S.N. M. No. 108669. 



DRUMASPIS, new genus 



This beautiful trilobite, represented by numerous species, carries 

 development of the Chariocephalus-Irvingella line in a logical direction 

 toward more normal trilobite structure by reducing eye size and en- 

 larging the posterolateral limbs. The brim always has a narrow pre- 

 glabellar area, but taken as a whole, the departure from the bar 

 structure, characteristic of the other komaspid genera, is not great. 



The quadrangular glabella is more or less tapered and usually has 

 rounded anterior angles. Occipital furrow deep. Three pairs of 

 glabellar furrows normally developed, the rear pair generally, and the 

 second pair sometimes, connected across the middle. Dorsal furrow 

 deep throughout. Fixigenes confined very largely to palpebral lobes 

 and posterolateral limbs. Eyes large, varying from less than half to 

 more than two-thirds the cranidial length ; usually set at an angle to 

 the cranidial axis. Eye bands wide. Brim narrow, of even width, 

 and its length equals the width of the rear portion of the glabella. 

 Thickened rim about as wide as preglabellar area. Anterior fixigenes 

 narrow. Anterior facial suture usually vertical, but sometimes diver- 

 gent. Posterolateral limbs fairly large in the smaller-eyed species. 



Libragenes small, with thickened rim. Ocular platforms narrow in 

 front, increasing in width posteriorly. 



Pygidium not found. Surface usually granulose. 



Genotype.— D. walcotti, new species. 



DRUMASPIS WALCOTTI, new species 



Plate 4, Figures 37-41 



This species has a long glabella which tapers slightly. Three pairs 

 of glabellar furrows are clearly discernible. The fixigenes vary con- 

 siderably in width owing to the strong curvature of the eyes. At their 

 widest point they are a little more than a third of the glabellar width. 

 The brim consists of a thickened rim and a slightly narrower pre- 

 glabellar area. The glabella is slightly arched in cross section, and 

 longitudinally curves considerably more, particularly in the anterior 

 portion. The conspicuously wide eye bands at once set the species off 

 from others found in the vicinity. 



