363 



with a flat border all round and a furrow close to the anterior margin ; 

 axis depressed convex, extending three-fourths the whole length, termi- 

 nating at the edge of the marginal flat border, not elevated at the apex, 

 distinctly defined at the sides by the dorsal furrows, about twelve narrow 

 but well defined rings. 



Length 5 lines ; width 9 lines ; width of marginal border 1 line ; width 

 of axis at the anterior margin 2| lines. 



This species is certainly closely allied to B. Saffordi (ante, p. 259), but 

 differs from it in having the border wider and flat instead of convex, and 

 in the axis having twelve instead of nine rings. These differences, although 

 slight, give to the specimen an aspect distinct from that of any variety of 

 B. Saffordi. 



Locality and Formation. Found loose at Hare Bay along with 0. 

 Murrayi. 



Collector. Alexander Murray, Esq. 



BATHYURUS GREGARIUS. (N. sp.) 



Fig. 349. 

 Fig. 349. Bathyurus gregarius. Part of head and thorax, drawn from a cast in plaster. 



Description. Ovate, from one to two inches in length. Head semi- 

 circular, broadly rounded in front and with an elevated rounded margin. 

 Glabella strongly convex ; sides nearly straight, apex rounded, separated 

 from the cheeks by deep dorsal furrows, a deep and wide groove in front 

 of it ; length including the neck segment full three-fourths the whole 

 length of the head ; neck segment rather large, rounded : neck furrow 

 well defined all across, Cheeks strongly convex. The eye is situated on 

 a line drawn across the head at one-third the length from the front margin, 

 distant from the dorsal furrow rather more than one-half the width of the 

 glabella. It appears to be a little more than one line in length where the 

 length of the head is six lines. Thorax with at least nine segments, the 

 precise number not known ; axis narrow, less than one-third the whole 



