I06 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 75 



MODOCIA OWENI (Meek and Hayden) 



Plate 16, figs. 1-3 



Arionellus (Creptcephalus) ozveni Meek and Hayden, 1861, Proc. Acad. Nat. 



Sci. Philadelphia, p. 436. (Original description of species.) 

 Arionellus ? oweni Meek and Hayden, 1862, Amer. Journ. Sci. Arts, ser. 2, 



Vol. 2)2, P- 74> fig- 4- (Description and illustration.) 

 Agraulos oweni Meek and Hayden, 1865, Pal. Upper Missouri, Smithsonian 



Contr. Knowl., Vol. 14, No. 172, p. g, figs. a-c. (Change of generic 



reference.) 

 Creptcephalus {Loganellus) centralis Whitfield, 1877, Prelim. Kept. Pal. 



Black Hills, U. S. Geol. Surv., p. 10. (Description.) 

 Crepicephalus centralis Whitfield, 1880, Rept. Geol. Res. Black Hills, U. S. 



Geogr. and Geol. Surv., p. 341, pi. 2, figs. 21-24. (Description and 



illustration.) 

 Ptychoparia oweni Walcott, 1884, Monogr. U. S. Geol. Surv., Vol. 8, p. 55, 



pi. 10, figs. 3, 3a. (Change of generic reference.) Grabau and Shimer, 



1910, N. A. Index Fossils, Vol. 2, p. 277. (Mentioned.) 

 Crepicephalus oweni Miller, 1889, North Amer. Geol. Pal., p. 540. (Generic 



reference.) 

 Anomocarella oweni Walcott, 1916, Smithsonian Misc. Coll., Vol. 64, No. 3, 



p. 204. (Generic reference.) 

 Modocia ozveni Walcott, 1924, Smithsonian Misc. Coll., Vol. 75, No. 2, p. 59, 



pi. 12, fig. 7. 



The generic description and the illustrations give all we know of 

 this species. 



Formalion and locality. — Upper Cambrian: Deadwood formation. 

 Castle Creek and Deadwood, Black Hills, South Dakota. Powder 

 River, Big Horn Mountains, Wyoming. 



Genus MOOSIA Walcott 



Moosia W^alcott, 1924, Smithsonian Misc. Coll., Vol. 75, No. 2, p. 59. 



Observations. — The genus Moosia is very much like Olenus in 

 many respects. The glabellar and dorsal furrows are very similar in 

 position, size and amount of depression. The eyes are also in very 

 nearly the same position and of the saine relative size. The three 

 characters of Moosia which exclude it from Olenus are, first, the 

 slight tapering of the glabella ; second, the slightly greater divergence 

 of the facial suture anterior to the eyes ; and third, the eye-lines which 

 here slope back whereas in Olenus they always run straight out from 

 the glabella or even forward. 



The pygidium associated with Moosia agrees in general appearance 

 with that of Olenus, but differs in the greater width of the axis and 

 character of furrows. 



Genotype. — Moosia grandis Walcott. 



Range. — Upper Cambrian : at present known only from the Rocky 

 Mountain?, of southeastern British Columbia. 



