186 ROYAL SOCIETY OF CANADA 



This species differs from the Swedish form figured by Angelin,' in hav- 

 ing a more direct suture before and behind the eye, and a longer eyelobe. 

 It differs from the same species as figured by Brogger - in the coui"se of the 

 dorsal suture, and in the less numerous joints in the rachis of the 

 pygidium. 



This species differs from Zacanthoides Eatoni (which appears to be a 

 Dolichometopus) in its more obscure glabellar furrows, its narrower area 

 in front of the eyes and narrower occipital ring, but as Z. Eatoni seems 

 to be a young head, these differences may be due to the immaturity of 

 the specimen.^ The distorted head figured with Olenoides Mareoui 

 appears, also, to be that of a Dolichometopus, though its condition of 

 preservation makes this uncertain.'' Bathyurus senectus of Billings has 

 relations to Dolichometopus, but differs in a more prominent glabella and 

 distinct glabellar furrows. 



Prof. W. B. Dwight has described a fauna occurring in limestone and 

 shale near Poughkeopsie. The species described are in Duchess county. 

 State of ISTew York ; they are not numerous, but are interesting, as show- 

 ing a grouping corresponding to that of the fauna described in this paper. 

 Three cephalic shields of a trilobite, described as Olenoides Stissifigensis, 

 are figured,^ of which the central one (fig. 15) appears to be a Dolicho- 

 metopus, and if it were not for the furrows represented on the glabella, 

 the two other heads would be referable, with equal reason, to that genus ; 

 the flat profile, figured with fig. 10, points to the same conclusion. But 

 we do not as yet know of any spined p3'gidia referable to the genus Doli- 

 chometopus, and the known examples of Dorypyge show a higher relief 

 to the head-shield. 



DORYPYGE, Dames. 



Mr. Walcott has placed a number of forms under Olenoides, Meek, 

 which, it seems to the author, more properly belong to the above genus. 

 Olenoides was a form of which Mr. 3Ieek had very imperfect material, 

 and the definition of the genus put forward by Mr. Walcott is based on 

 Meek's Paradoxides{f) Nevadensts, and Walcott's own Olenoides typicalis, 

 chiefly the latter. In this genus (1886) the latter author has placed a 

 good many diverse forms, and among them a group of species which is 

 excluded by those points in the diagnosis of the genus which relates to 

 the eyes and the course of the dorsal suture. 



1 Palseontolog. Scand., pi. xxxvii., figs. 9 and 9 b and c. 



2 On Paradox, skifrene v. Krekling, tab. iii., flgs. 12 and 12 a. 



3 Fauna of the Olenellus Zone, pi. xciv., fig. 6. 

 * Ibidem, tig. 2. 



8 Am. Jour. Sci., vol. xxxviii., Aug., 1889, p. 139, pi. vi. 



