NO. 4 CAMBRIAN TRILOBITES, 2D CONTRIBUTION RESSER Q 



Billings' description and illustration are inadequate to identify the 

 species. Subsequently, Matthew restudied the type preserved at Ot- 

 tawa, concluding that it is not the holotype but a specimen substituted 

 by Billings for it. However, since the figures of both authors clearly 

 indicate a form with expanded glabella, and since this specimen is the 

 only such form among the types, it may be regarded as Matthew's 

 neoholotype. 



All specimens from other localities identified as B. senecfa belong 

 to other species. Those illustrated by Walcott in 1916 from Bonne 

 Bay and Quebec must be studied with the great number of new species 

 in hand from those localities before they can be placed in their proper 

 species. 



Coinparisons:- — Comparing B: senecfa with the other species in Lab- 

 rador, it is at once distinguished by its long, expanding glabella, the 

 rather strong glabellar furrows, and the rounded frontal outline. 



Occurrence same as preceding. 



Neoholotype.— 'Na.t. Mus. Canada no. 420. 



Bonnia columbensis, n. sp. 



Coryiic.rochus {Bonnia) seyiectus Walcott, Smithsonian Misc. Coll., vol. 64, 

 no. 5, p. 319, pi. 55, figs. 7-7C, 1916. 



Compared with B. senecta, this species is very simple. Its outstand- 

 ing characteristic is the rounded lines in all its parts. Fusion is car- 

 ried far in the pygidium. 



Lower Cambrian, Mount Whyte ; (loc. 6id) southwest slope of 

 Mount Shaflfer, British Columbia. 



Lcctotype. — U.S.N.M. no. 62'/22 ; paratypes, nos. 62723-62725. 



Bonnia clavata (Walcott) 



Ptychoparia? (Subgenus?) clavata Walcott, Amer. Journ. Sci., 3d ser., 



vol. 34, p. 198, pi. I, fig. 3, 1887. 

 Corynexochus clavatus Walcott (part), Smithsonian Misc. Coll., vol. 64, no. 



5, p. 316, pi. 55, fig. 4, 1916 (not fig. 4b == B. salemensis; fig. 4a is a 



worthless composite drawing). 



This is a very small trilobite, and the specimens include at least two 

 species. In the first place the composite drawing used in 1887 and 

 subsequently repeated in 1891 and 1916, must be discarded both be- 

 cause it is incorrectly drawn and because it is based on at least two 

 species. Further, figure 4 of the 1916 paper, which is the holotype of 

 the species, needs correction. Carefully made enlarged photographs 

 show no more trace of glabellar furrows than the smooth glabella indi- 

 cates under a lens. In addition this head is crushed so that the expan- 

 sion of the glabella is somewhat accentuated. With allowance for this 



