22 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 95 



DASOMETOPUS, n. gen. 



This peculiar trilobite was originally referred by Angelin to Har- 

 pides. Subsequently, Gronwall placed it in the invalid genus Erinnys, 

 thus including the species in Bailiella. Only a brief examination is 

 necessary to show that this form is not Bailiella; consequently, a new 

 genus must be made for it. 



Diagnosis. — Cephalon alone known. Cephalon semicircular, eye- 

 less. Glabella well defined, tapered, a little more than half the length 

 of the head. Glabellar furrows present, the rear pair recurved, sepa- 

 rating marginal lobes. Cheeks marked by irregular lines radiating 

 from the dorsal furrow. Upturned rim with coarse granules ; other 

 scattered granules on cheeks. A depression extends across the pre- 

 glabellar area. 



Comparisons. — Dasometopus is similar to Holocephalina in many 

 respects. It differs in its greater relative width and particularly in the 

 depression extending from the glabella to the anterior furrow. From 

 Bailiella it is also differentiated by this depression. 



Genotype.- — -Harpides breviceps Angelin. 



Range. — Middle Cambrian of the Atlantic Province. 



Name. — 8acri's = rough, /^erooTrov^ forehead. 



Dasometopus breviceps (Angelin) 



Harpides breviceps Angelin, Pal. Scand., 3d ed., Holmiae, p. 87, pi. 41, fig. 8, 



1878 (ist ed., 1854). 

 Couocoryphe (Erinnys) breviceps Gronwall, Danmarks Geol. Unders., vol. 2, 



no. 13, p. 97, 1902. 



Middle Cambrian, Andrarum ; Andrarum, Sweden and Bornholm, 

 Denmark. 



CORYNEXOCHIDAE Angelin, 1852 



CORYNEXOCHUS Angelin, 1852 



Corynexochns Angelin, Pal. Scand., 3d ed., Holmiae, p. 59, 1878 (earlier edi- 

 tions 1852, 1854). 

 Corynexochns Gronwall, Danmarks Geol. Unders., vol. 2, no. 13, p. 136, 1902. 

 Corynexochns Walcott, Smithsonian Misc. Coll., vol. 64, no. 5, p. 309, 1916. 

 Corynexochns Raymond, Amer. Journ. Sci., vol. 15, p. 309, 1928. 

 Corynexochns Lake, Mon. British Camb. Tril., Pal. Soc, pt. 8, p. 180, 1934. 

 Karlia Walcott, Proc. U. S. Nat. Mus., vol. 11, p. 444, 1880. 



Angelin founded Corynexochns on a cranidium, but as pointed out 

 by Lake, the specific name of the genotype evidently was based on a 

 spinose tail. Some doubt still remains regarding the pygidium, but 

 Gronwall's assignment of a small pygidium to Angelin's species ap- 

 pears to be correct. 



