Xmatthew] studies ON CAMBRIAN FAUNAS 197 



Sculpture. — This consists of anastomosing raised lines (as in several 

 species of Paradoxides) on the front half of the glabella ; these become 

 broken into a granulated surface on the back of the glabella and cheeks, 

 with finer granulations in the furrows than elsewhere. The anterior 

 marginal fold has fine parallel raised lines, and is convex, becoming 

 flatter toward the dorsal suture. 



The whole contour of the head-shield of this species is very Para- 

 doxides-like, the difference from Paradoxides being in the more direct and 

 shorter anterior extension of the dorsal suture and the obsolete third 

 furrow on the glabella; the glabella, also, is more squarely rounded in 

 front than in Paradoxides. As a connecting form between this genus and 

 the western Bathyurisci, Billings's species is of interest. 



DOEYPYGE, Dames. 

 DoRYPYGE PARVULA, Billiugs sp. (PI. IV., figs. 5 and 5 a.) 



Bath i/urus par vulus. Bill., Geol. Vermont, vol. ii, p. 95:3. 



Bathyurus parvjilus. Bill., Palaeozoic Fossils, vol. i., p. 16, fig. 21. 



Protypus senectus (part), Walcott, U. S. Geol. Surv., Bull. 30, p. 213, pi. xxxi 

 fig. 2 a. 



Protypus senectus (part), Walcott, Fauna of Olenellus Zone, p. 655, pi. xcviii., 

 fig. 7 a. 



On examining Billings's type specimens I find them to consist of a 

 cast of the middle piece of the head-shield in fine sandstone, and five 

 examples of the same portion of the head in limestone. The limestone is 

 of three different textures, and one larger varietal form in gray limestone 

 is marked as from Long Beach, Anse au Loup. 



The head in sandstone appears to have been the one figured by 

 Billings, as it is of the "size and proportions described and figured by him, 

 but the description of the surface markings seem to have been based on 

 the examples in the limestone, most of which are smaller than that in 

 the sandstone. I think the cast in sandstone differs enough to be a 

 variety, as the glabella is sensibly narrower, and there is scarcely a trace 

 of furrows on it. Billings says that Scolithus linenaris was the only fossil 

 found in the sandstone at Anse au Lovip, so we vany presume that the 

 heads preserved in lijnestone are the types ; the cast is, therefore, dis- 

 tinguishable as var. am/ifroiis (PI. IV., figs. 6 and 6 a.), and may pos- 

 sibly be from a Vermont locality.* 



In the limestone fossils the ocular fillet is far forward on the cheek, 

 close to the anterior marginal furrow : it was most distinct near the 

 glabella. 



1 I have, through the favour of Dr. Ami of the Canadian Geological Survey, the 

 head of a Dorypjge collected from sandstone at Port Henry, N.Y., by Prof. H. M. 

 Seely, which is not unlike Billings's D. parvula. It has a somewhat wider glabella. 



