NO. 12 SPENCE SHALE AND ITS FAUNA RESSER I7 



cranidimn. In keeping with that narrowness, the trilobite as a whole 

 is more slender. 



Localities 55c, 55e, and 20x. 



Holotypc and paratypcs. — U.S.N.M. no. 96516. 



ALOKISTOCARE LATICAUDUM, n. sp. 



Plate 4, figs. 15-19 



This species is characterized by a wide brim and wide, long, genal 

 spines, a wide pygidium and 17 thoracic segments. The genal spines 

 extend back to about the 14th segment. Fusion has not obliterated 

 pleural furrows in the pygidium. 



Localities 55c and 55e. 



Holotypc and paratype. — U.S.N.AL nos. 96517, 8. 



ALOKISTOCARE SEPTUM, n. sp. 



Plate 4, figs. 5-7 



This is a wide-tailed form like A. laticauduin. It dilYers in having 

 a narrower glabella. But the distinctive feature is the great genal 

 spines which extend almost to the pygidium. 



Locality 55c. 



Holotypc and paratype. — U.S.X.IM. no. 96520. 



ALOKISTOCARE PUNCTATUM, n. sp. 



Plate 4, figs. 20, 21 



Reduction of brim brings this species closer to Cliancia, than most 

 species referred to Alokistocare. But since a rim is not diiTerentiated 

 by thickening, this form is called Alokistocare. 



The cranidium is rather wide and the anterior margin not so much 

 curved. On exfoliated specimens the eye lines are heavy and the 

 surface is strongly punctate. One specimen retains 15 thoracic seg- 

 ments, indicating a thorax of possibly 20 segments. 



Locahty 55e. 



Holotypc and paratypcs.— U.S.N.M. no. 96519. 



CHANCIA Walcott, 1924 

 CHANCIA EBDOME Walcott 



Plate 4, figs. 12-14 



Cliancia ebdoiiie Walcott, Smithsonian Misc. Coll., vol. 75, no. 2, p. 55, pi. 10, 

 fig. 4, 1924. Idem, no. 3, p. 80, pi. 17, fig. 26, 1925. 



Locality 55c. 



Holotype.—U .S.N .M. no. 70274. 



