234 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 64 



DESCRIPTION OF PLATE 26 



PAGE 



Acrocephalites ? niajus Walcott 180 



Fig. I. (Natural size.) Large cranidium doubtfully referred to this 

 genus. U. S. National Museum, Catalogue No. 61578. 

 The specimen illustrated is from the Middle Cambrian: (4g) 

 Wolsey shale: i mile (1.6 km.) north of forks of East and West 

 Gallatin Rivers, Gallatin County, Montana. 



Acrocephalites ? vulcanus (Billings) 182 



Fig. 2. (X 3-) Cranidium from the type locality of the species. U. S. 

 National Museum, Catalogue No. IS437- 

 From Lower Cambrian: (25) Shaly sandstone just above 

 Parkers Quarry, Georgia, Franklin County, Vermont. 



This is the original of fig. 4, pi. 26, Bull. U. S. Geol. Survey, 

 No. 30, 1886. 



Acrocephalites aoris Walcott 178 



Fig. 3. (X 2.) Dorsal view and side outline of cranidium. U. S. 

 National Museum, Catalogue No. 61579. 

 2a. (Natural size.) The same cranidium as that represented by 



fig. 3- 

 3&. (X I-5.) A broken cranidium showing occipital ring. U. S. 

 National Museum, Catalogue No. 61580. 

 The specimens illustrated are from locality loyd, Middle Cam- 

 brian: Conococheague ? limestone; i mile (1.6 km.) north of Henri- 

 etta, Blair County, Pennsylvania. 



Menomonia calymenoides (Whitfield) 162 



Figs. 4, 4'. (X2.) Dorsal view and side outline of an entire cra- 

 nidium. U. S. National Museum, Catalogue No. 61581. 



4a, 4a'. (X2.) Dorsal view and side outline of a broken cra- 

 nidium. U. S. National Museum, Catalogue No. 61582. 



46. (Natural size.) A nearly entire specimen of the thorax, 

 pygidium, and base of cephalon with 42 thoracic segments. 

 U. S. National Museum, Catalogue No. 61583. 



4c. (X2.) Same as fig. 4b with photograph retouched to bring 

 out thoracic segments. 



4d. (X2.) Free cheek associated with the specimen represented 

 by fig. 40. U. S. National Museum, Catalogue No. 61584. 



The specimens illustrated by figs. 4, 4a-d are all from the Eau 

 Claire formation of the Upper Cambrian. Fig. 4, from locality 100, 

 near Menomonie, and figs. 4a and 4^ from locality 83a, Rock Falls, 

 both in Dunn County, Wisconsin. Figs. 4b-c are from locality 98, 

 near Eau Claire, Eau Qaire County, Wisconsin. 



Dresbachia amaia Walcott 167 ■ 



Figs. 5.5'. (X4-) Dorsal view and side outline of a cranidium, pre- 

 serving the projecting frontal rim with its deep median 

 furrow. U. S. National Museum, Catalogue No. 61585. 



