yO SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 75 



essential feature from Platypeltis Galloway except that its eyes are 

 smaller. Heinigyraspis, as based on McCoy's species, may be a sub- 

 genus of Platypeltis, or perhaps of Symphysurus, but not of Niobe. 

 Again, Heinigyraspis afUnis seems a close relative of Asaphellus with 

 which it agrees in every generic character, except that the facial 

 suture in the former cuts the anterior edge of the cephalon in front 

 of the eye, whereas in the typical species of Asaphellus the suture 

 remains on the dorsal side to the middle of the anterior edge. In 

 view of these facts it is difficult to decide as to which of these sug- 

 gested alliances is the closest. Personally, I doubt very much that 

 we know enough of these trilobites to warrant any definite conclusion. 

 For the present, therefore, I prefer to view Heinigyraspis as a distinct 

 genus, and would refer to it only those species that are unquestionably 

 congeneric with the type species. 



" Thus restricted it becomes questionable whether the genus is truly 

 represented in American deposits. Raymond refers here Matthew's 

 Asaphellus f planus^ but that Bretonian species is described as having 

 an unlobed pygidium, on which account its reference to Heinigyraspis 

 seems very doubtfully warranted. He describes also two new species, 

 one of which, H. mcconnelli^ from the vicinity of Golden, British 

 Columbia, is based on specimens too- imperfect for exact determina- 

 tion. The other is founded on separated pieces of a trilobite collected 

 at Belief onte. Pa., from near the top of the Stonehenge limestone, 

 which is the lowest of four alternating limestone and dolomite for- 

 mations into which the great development of the Canadian system in 

 central Pennsylvania has been divided. Raymond ' applied the name 

 Hemigyraspis collieana to this Bellefonte species. 



" Unfortunately, the specimens on which Raymond based this 

 species, especially that, or those of the cranidium, are so imperfect 

 that he failed entirely to observe certain important characters that 

 are quite at variance with those assigned to his genus Hemigyraspis. 

 Thus, in H. collieana the glabella is clearly outlined in front — as well, 

 indeed, as in any asaphid ; and in front of it the cranidium incloses 

 a fairly wide flat border. The facial suture does not cut the front 

 edge of the cephalon, as in H. afUnis, but, as shown by the anterior 



^ Matthew, G. R, 1902, Bull. New Brunswick Nat. Hist. Soc. No. 20, p. 419, 

 pi. 18, fig. 11; Geol. Survey Canada Ann. Rept. 1903, Cambrian Rocks Cape 

 Breton, p. 237, pi. 18, fig. 11. 



^Raymond, P. E., 1913, Victoria Mem. Mus. Bull. No. i, p. 40, pi. 4, fig. 4. 



^ Raymond, P. E., 1910, Annals Carnegie Mus., Vol. 7, p. 41, pi. 14, figs. 9-13. 



