Point Levi Fossils* 317 



Menocephalus globosus. N. s. 

 Fig. 17, 18, 19. 



Description. — Head globose, the posterior angles produced in- 

 to small slender spines directed outwards, at an angle of about 

 45°, with the axis of the body. Glabella exceedingly convex, 

 almost hemispherical, its length slightly exceeding its width ; 

 either totally destitute of lateral furrows, or with two inconspic- 

 uous indentations on eaeh side. Keck furrow and segment well 

 defined ; the margin of the head with a narrow, wire-like border 

 all round, which turns up in front of the glabella, and forms an 

 obtusely pointed rostrum ; cheeks moderately tumid, but droop- 

 ing on each side, so as to give a great depth to the outline of the 

 head. Eyes about one-fifth the total length of the head, situa- 

 ted opposite the mid-length of the glabella, and about their own 

 width from it. Facial suture as in A, suhclavatus. Surface 

 covered with small tubercles. Width of head in the specimen 

 figured five lines ; length, three lines ; length of glabella, two 

 lines and one-fourth. 



Associated with these are very numerous glabellae of a larger 

 size, in general four lines in length, which probably belong to 

 this species. 



Limestone No. I. 



Genus Bathturus. Billings. 



This genus was described in the "Canadian Naturalist and 

 Geologist," vol. 4, p. 364, in the article on the fossils of the Cal- 

 ciferous Sandrock. Tt differs from Asaphus by having nine seg- 

 ments in the thorax, the front of the hypostoma not forked, and 

 the glabella well defined by the dorsal furrows. It somewhat re- 

 sembles both 31egalaspis and JSliohe (^ngelin), in the form of the 

 glabella, but the hypostoma is precisely like that of Ogygia. I 

 have some evidence to shew that the head is composed of three 

 pieces only, as in Dikelocephalus. The species heretofore de- 

 scribed are, B. amjylimarginatus, B. conicus, and B. Cyhele^ 

 from the Cnlciferous Sandrock : — B. Angelini, Chazy : — B. extans, 

 (^Asaphus extansy Hall,) as yet known only in the Black River 

 limestone, and B. spiniger, {Acidaspis spiniger, Hall.) This 

 latter species occurs both in the Black River and Trenton, in 

 Canada. 



The following species are referred to this genus provisionally. 

 I am not at all satisfied that they belong to the genus, but I know 

 of no other to which they bear so near a resemblance. 



