NO. 4 CAMBRIAN TRILOBITES, 2D CONTRIBUTION RESSER 5 



the rim flatter. Also the thorax is somewhat longer, but the chief dii- 

 ference is in the pygidium. Armonia has a transverse pygidium, 

 whereas that of Blainia is almost quadrate and moreover is more con- 

 vex. Further comparisons will appear in the discussion of other simi- 

 lar genera. 



Genotype. — Asaphiscus (Blainia) elongatus Walcott (part). 



Range. — Middle Cambrian of the southern Appalachians. 



Armonia elongata (Walcott) 



Asaphiscus (Blainia) elongatus Walcott (part), Smithsonian Misc. Coll., 

 vol. 64, no. 5, p. 393, pi. 63, figs. 4, 4a, 1916. (Pygidium represents another 

 genus.) 



Armonia pelops Walcott, Smithsonian Misc. Coll., vol. 75, no. 2, p. 54, pi. 10, 

 fig. I, 1924; idem, no. 3, p. 69, pi. 17, figs. 28-31, 1925. 



When the specimens contained in the chert cobbles were first de- 

 scribed, an incorrect pygidium was chosen. Later when the same 

 species occurring in the dark shales containing the nodules was de- 

 scribed, new generic and specific names were used. 



Middle Cambrian, Conasauga (Rogersville equivalent) ; (Iocs. 90X, 

 95, 92) southeast of Center, Cherokee County, Alabama. 



Lecfotype. — U.S.N.M. no. 62812; paratypes, no. 6281 1 ; plesio- 

 types. nos. 72276-72279. 



BONNASPIS, n.gen. 



The Middle Cambrian species from Mount Stephen, British Colum- 

 bia, on which Walcott evidently planned to base his genus Karlia, does 

 not belong to Corynexochus, of which Karlia minor is a good species. 

 In consequence K. stephenensis becomes the type of a new genus for 

 which the name Bonnaspis seems appropriate, inasmuch as a relation- 

 ship with Bonnia is evident. 



Diagnosis. — Small trilobites oval in shape, with subequal head and 

 tail shields. Glabella of moderate size, expanded forward, with faint 

 furrows. Eyes small, situated at the midpoint. Fixed cheeks moder- 

 ately wide, with eye lines. 



Free cheeks narrow with long and heavy genal spines. 



Thorax with seven segments ; pleura bluntly terminated. 



Pygidium wider than distance between eyes, semicircular, well 

 fused, with axial and pleural furrows shallow. Pleural furrows ex- 

 tend to margin. 



Genotype. — Karlia stephenensis Walcott. 



Range. — Rare in the Middle Cambrian of British Columbia. 



Comparisons. — Comparing Bonnaspis with Bonnia, the outstanding 

 distinction is the expansion of the glabella and the apparent absence of 



