NO. lO CAMRRIAN FOSSILS, 4TH CONTRIBUTION RESSER 33 



Elvinia matheri (Walcott) 



Ptychoparia mafheri Walcott, Smithsonian Misc. Coll., vol. 57, no. 9, p. 268, 

 pi. 44, figs. 15-17, 1912; Bridge (part), U. S. Geol. Surv. Prof. Pap. 

 186- AI, p. 254, pi. 69, fig. II, 1937. 



Upper Cambrian, Potsdam; (loc. no) east side of Whitehall, 

 New York. 



Cotypcs.—U.S.^M. nos. 58585-7. 



GENE VIE VELLA Lochman, 1936 



GcncvicveUa Lochman, Journ. Pal., vol. 10, no. i, p. 40, 1936. 

 Llanoaspis Lochman, idem, vol. 12, no. i, p. 80, 1938. 



When this genus was established, only the genotype was known. 

 Two species were added from Texas, and the descriptions of eleven 

 from the Appalachians are in press ; consequently this is a well- 

 represented trilobite genus. Thus far the genus is confined to the 

 Crepicephalus zone. 



Llanoaspis modest a and L. undiilata Lochman become Gene- 

 vievella. 



IRVINGELLA Ulrich and Resser, 1924 



Irvingella was applied to species which differ from Chariocephalus 

 in a limited degree. Chariocephalus has large eyes situated rather 

 far forward. The facial suture joins the dorsal furrow anterior to 

 the eye, by which arrangement the anterior fixigene is eliminated 

 and the brim is caused to be a single bar not attached to the lixigenes 

 at the anterior angles. On the other hand Irvingella has e\'en larger 

 eyes than Chariocephalus, the extra length being attained by the rear 

 portion of the palpebral lobes extending farther back. At the same 

 time the eyes are slanted outward from the axis of the head. Above 

 all, Irvingella differs from CJiariocephalus by having anterior fixigenes 

 which unite with the brim. 



Irvingella tumifrons (Hall and Whitfield) 



Chariocephalus tumijrons H.\ll and Whitfield, U. S. Geol. Expl. 40t]i Par., 

 vol. 4, p. 224, pi. 2, figs. 38, 39, 1877. 



Upper Cambrian, Secret Canyon; Pogonip ^Mountain, White Pine 

 District, Nevada. 



Holofype. — U.S.N.M. no. 24561. 



KOCHINA Resser, 1935 



Kochina? lux (Walcott) 



Ptychoparia lux Walcott, Smithsonian Alisc. Coll., vol. 67, no. 3, p. 90, 

 pi. 12, fig. 5, 1917. 



