NO. lO CAMBRIAN FOSSILS, 4TH CONTRIBUTION RESSER 37 



OLENOIDES Meek, 1877 



Olenoides expansus (Walcott) 



Dicellocephahis ? expansus Walcott, U. S. Geol. Surv. Mon. 8, p. 45, pi. 9, 



fig. 19, 1884. 

 Dolichometopus ? expansus Walcott, Smithsonian Misc. Coll., vol. 64, no. 5, 



p. 368, pi. 53, figs. 5, 5a, 1916. 



Middle Cambrian, Eldorado; (loc. 55b) east slope Prospect Moun- 

 tain, Eureka District, Nevada. 

 Holotype.—U.S.'NM. no. 15450. 



ORYCTOCEPHALUS Walcott, 1886 



Species of this genus have not been carefully discriminated, and 

 specific names were very carelessly used. A brief revision clears the 

 way for* erection of the necessary new species. 



Oryctocephalus, as now constituted, contains two groups of species. 

 The valid species previously recognized are listed under the two groups. 



Group of O. primus (genotype) O. zvalcotti Resser 



O. primus Walcott O. salteri Reed 



O. burgessensis, n. sp. O. indicus (Reed) 



O. ivalkcri Matthew O. kobayaski Saito 



Group of O. rcynoldsi O. orientalis Saito 



O. reynoldsi Reed O. saitoi, n. sp. 



In addition, one undescriljed species of the 0. priunis group and 

 several of the O. rcynoldsi group are in hand. 



Oryctocephalus burgessensis, n. sp. 



Oryctoccphahts primus Kobayashi, Journ. Faculty Sci. Imp. Univ. Tokyo, 

 sec. 2, vol. 4, pt. 2, p. 147, pi. 15, fig. I, 1935. 



Kobayashi picked up a photograph in the National Museum collec- 

 tions and published it as 0. priuins, but this illustration was pre- 

 pared by Walcott because he recognized that it was not 0. primus. 



0. bitrgcssoisis is the most abundant species of the genus in the 

 Burgess shale. It is characterized by a normal cranidium, seven tho- 

 racic segments, and slender pygidial spines of even length. The rear 

 segments of the pygidium are turned back practically parallel to the 

 axis. The pygidial spines of even length cause this species to look 

 much like O. n'cilkcri, hut the rear pygidial segments are turned back 

 more sharply. 



Middle Cambrian, Burgess; (loc. 35k) Burgess Pass, near Field, 

 British Columbia. 



Holotypc.—V.S.NM. no. 96487. 



