NO. 13 DIKELOCEPHALUS AND OTHER GENERA 367 



In 1913, Dr. p. E. Raymond proposed the genus Platycolpus and 

 referred Whitfield's species Dikelocephalus barabuensis and D. 

 catoni to it.^ 



The species now referred to the genus as restricted are : 



Dikelocephalus minnesotensis Owen (pis. 60, 61, 62, 65) 

 Dikelocephalus minnesotensis van undt. (pi. 61, fig. 4) 

 Dikelocephalus ? dalyi Walcott (pi. 64, figs, i-s) 

 Dikelocephalus hartti (Walcott) (pi. 63, figs. 1-7, ya) 

 Dikelocephalus ? limbatus Hall (pi. 65, figs. 5-8) 

 Dikelocephalus texanus Walcott (pi. 65, fig. 4) 

 Dikelocephalus ? tribulis Walcott (pi. 63, figs. 8-10, loa) 

 Dikelocephalus vanhornei Walcott (pi. 62, figs. 1-3) 

 Dikelocephalus sp. undt." (loc. 151) 



DIKELOCEPHALUS ? DALYI, new species 



Plate 64, figs. 1-5 



This fine species is founded on fragments of a large trilobite that 

 include the cranidium, portions of thoracic segments and nearly entire 

 pygidia which occur in limestone nodules embedded in a calcareous 

 shale. 



The smaller cranidia have the general outline of some of the species 

 of Anomocare and Anomocarella from the Chinese Cambrian/ but the 

 larger specimens have the broad, flattened frontal limb of Dikelo- 

 cephalus. (Compare fig. 2, pi. 64, and fig. 5, pi. 61.) The palpebral 

 lobe of D. dalyi is shorter than in typical Dikelocephalus, in this 

 respect resembling some species of Anomocare, but not the typical 

 species, Anomocare Iceve Angelin. The glabella is also much like that 

 of Anomocare, but it might be included under Dikelocephalus by its 

 outline and strong occipital ftirrow and long posterior glabella fur- 

 rows. The associated free cheek might be referred to either genus 

 a.i it has the general characters of each. 



The fragments of the thoracic segments are similar to correspond- 

 ing parts of the thoracic segments of Dikelocephalus and, to a less 

 degree, of Anomocare. 



The associated pygidia are essentially the same as the pygidium of 

 Dikelocephalus hartti (pi. 63) and D. minnesotensis, with the excep- 

 tion of not having the two marginal spines of the latter species. 



Dikelocephalus ? dalyi attains a much larger size than any known 

 species of Anomocare, in this being comparable with Dikelocephalus. 



* Geol. Survey Canada, Victoria Mem. Mus., 1913, Bull. 1, pp. 63, 64. 

 ^ See footnote ^ p. 391, this paper. 



' Research in China, Vol. 3, Carnegie Institution of Washington, Pub. No. 

 54, 1913, The Cambrian Faunas of China, pis. 18 and ig. 



