NO. 5 CAMBRIAN TRILOBITES RESSER 17 



DESCRIBED SPECIES REFERRED TO BLAINIA 



Blainia gregaria (Walcott) 



Asaphisciis (Blainia) grcgarius Walcott (part), Smithsonian Misc. Coll., 

 vol. 64, no. 5, p. 394, pi. 62, figs. I, ib-ii (not ia:= B. cenfcrcnsis) , 1916. 



It is possible that, even with the specimen figured as la eliminated 

 because it has lo instead of 9 segments, more than one species still 

 remains. 



Middle Cambrian, Conasauga; (loc. 90) 3 miles southeast of Center, 

 Alabama. 



Lectotype and paratypes. — U.S.N.M. nos. 62797 and 62791, 

 62793-6, 62798-62801. 



Blainia centerensis, n. sp. 



Asaphisciis {Blainia) gregarius Walcott (part), Smithsonian Misc. Coll., vol. 

 64, no. 5, p. 394, pi. 62, fig. la, 1916. 



This form has 10 instead of 9 thoracic segments. 

 Occurrence same as preceding. 

 Holotype. — U.S.N.M. no. 62792. 



BOLASPIS, n. gen. 



A rather large group of Cambrian trilobites, usually referred to 

 Acrocephalites and Alokistocare because of the highly developed boss 

 in the center of the preglabellar field, has long needed a generic name. 



Diagnosis. — Cranidium characterized by a conical glabella, with one 

 or more pairs of rather sharply reflexed furrows ; fixed cheeks wide 

 and tumid ; eyes small and sometimes stalked ; large rounded or tri- 

 angular elevation in preglabellar field ; rim usually flat and erect, 

 particularly in the middle ; neck ring heavy, sometimes extended into 

 a spine. Thorax and pygidium unknown. 



Comparisons. — When Acrocephalites was first described from frag- 

 mentary specimens, which fail to give a true concept of the genus, 

 the conical glabella and the boss in the preglabellar area were the sole 

 generic features apparent. However, after the genus came to be un- 

 derstood, it was apparent that the American species have only a few 

 superficial resemblances and are not related to it. 



Comparing Bolaspis with Alokistocare, we find little similarity ex- 

 cept in the possession of the median boss. Bolaspis has a much more 

 tapering glabella, its preglabellar area is reduced to triangular form 

 by the down-turned anterior angles, and it lacks the vertical striations 

 crossing the brim. 



Genotype. — Alokistocare ? labrosinn Walcott. 



Name. — BoAos= lump, and ao-7rt9 = shield. 



Range. — Apparently confined to the Middle Cambrian. 



