NO. lO CAMBRIAN FOSSILS, 4TH CONTRIBUTION RESSER 21 



Matthew erected the genus Camarothcca for the hyohthid forms 

 which show internal septa and a structure analogous to the cephalopod 

 siphuncle. Examination of many species shows that cameration de- 

 pends on preservation and may be found in any species. The other 

 genera excepting Camarotheca are apparently all valid, or at any rate 

 express definite and distinctive structures. 



Orthotheca Novak is valid only for Ordovician organisms, which 

 are unrelated to the rounded tubes ofttimes placed in Hyoli flies. 

 Therefore, the practice, followed by the author and others, of as- 

 signing tapered tubes with circular cross-section to OrthotJieca, is 

 improper. 



Revision of Cambrian Hyolithidae is greatly needed. Not only 

 must a series of genera be established but the species themselves have 

 been so carelessly handled that most are of little value. Recent strati- 

 graphic studies occasioned review, in part, of H. primordialis and 

 H. billingsi. Several of the resulting nomenclatural changes are 

 recorded below.- 



Hyolithes gregarius (Meek and Hayden) 



Theca (Pngiiiiiciiliis) gregaria Meek and Hayden, and Proc. Acad. Nat. 



Sci. Philadelphia, p. 436, 1861 ; Amer. Journ. Sci., 2d ser., vol. 33, p. yi, 



text fig. 3, 1862. 

 Thcca gregaria Meek and Hayden, Pal. Upper Missouri, Smithsonian Contr. 



Knowl., vol. 7, p. 5, text figs, a-d, 1865. 



This species averages much smaller than H. primordialis to which 

 it was referred and, therefore, is again recognized. 



Upper Cambrian, Depass ; Powder River, Big Horn Mountains, 

 Wyoming. 



Cotypes. — U.S.N.M. no. 1181. 



Hyolithes gallatinensis, n. sp. 



Hyolithes primordialis Walcott (part), U. S. Geol. Surv. Mon. 32, pt. 2, 

 p. 454, pi. 63, fig. 2, 1899. 



This wade species is characterized by a very slightly convex pos- 

 terior surface and an evenly, semicircular anterior side. The surface 

 is smooth in the specimens available but they may be interiors only. 

 The lingual extension is broken away. 



Upper Cambrian, Dry Creek; (loc. 151c) Crowfoot Ridge, Galla- 

 tin Range, Yellowstone National Park, Wyoming. 



Holotypc.—US.NM. no. 35218. 



Hyolithes whitei, n. sp. 



Hyolifhcs primordialis ? White, Geogr. Geol. Expl. Surv. West looth Merid., 

 Prelim. Rep. Invert. Foss., p. 6, 1874. Idem, vol. 4, pt. r, p. 2,7, pi. i, 

 figs. 5a-e, 1875. 



