NO. 5 CAMBRIAN TRILOBITES RESSER 1 5 



It is possible that the ilkistrated pygidium does not belong to the 

 species. 



Middle Cambrian, Conasauga ; (loc. i6e) i mile southwest of Pied- 

 mont, Alabama. 



Holotypc. — U.S.N.M. no 62665; paratype (?), no. 62666. 



SPINED GROUP OF BATHYURISCUS 



It may prove desirable to separate these forms as a distinct genus. 



Bathyuriscus adaeus Walcott 



Bathyui'iscus adaeus Walcott, Smithsonian Misc. Coll., vol. 64, no. 5, p. 334, 

 pi. 47, figs. 3-2C, 1916. 



In most respects this species is much like B. rofundatus, but the 

 anterior pygidial segment is extended beyond the margin into spines. 

 The published illustrations fail to show correctly the full length or 

 direction of the spines, which turn backward and reach about to the 

 posterior end of the axis. Further, this spine interrupts the rim and 

 does not arise from it. 



The specimen from locality 61 j identified as this form represents 

 another species. 



Middle Cambrian, Stephen; (loc. 58J) IMount Stephen, near Field, 

 British Columbia. 



Cotypes. — U.S.N.M. nos. 62631-4. 



Bathyuriscus atossa Walcott 



Bathyuriscus atossa Walcott, Smithsonian Misc. Coll., vol. 64, no 5, p. 336, 

 pi. 48, figs. 2-2b, 1916. 



Middle Cambrian, Spence ; (loc. 55c) Liberty Canyon, west of 

 Montpelier, Idaho. 



Lectotype. — U.S.N.M. no. 62642 ; paratypes, nos. 62643-4. 



Bathyuriscus marjumensis, n. sp. 



Bathyuriscus ? sp. uiidet. Walcott, Smithsonian Misc. Coll., vol. 64, no. 5, 

 p. 348, pi. 65, fig. 5, 1916. 



Presumably this form falls within the spined group of Bathyuriscus. 

 If it rightly belongs here, it is apparently the youngest species of the 

 genus known. 



Middle Cambrian, Marjum; (loc. up) 2^ miles southeast of 

 Marjum Pass, House Range, Utah. 



Holotype. — U.S.N.M. no. 62845. 



