232 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 64 



DESCRIPTION OF PLATE 25 



PAGE 



Acrocephalites insignis Walcott 179 



•Fig. I. (X4-) Cranidium with strong palpebral lobes, and ridges 

 crossing fixed cheeks. U. S. National Museum, Catalogue 

 No. 61568. 

 la. (X 4-) Nearly entire dorsal shield crushed in the shale. U. S. 



National Museum, Catalogue No. 61569. 

 lb. (X4-) A cranidium and part of thorax. Free cheek and out- 

 line of eye preserved. U. S. National Museum, Catalogue 

 No. 61570. 



The specimens represented by figs, i, Ja-b are from locality 

 112, Middle Cambrian: Conasauga shale; east of Center, Cherokee 

 County, Alabama. 



Alokistocare subcoronatum (Hall and Whitfield) 187 



Fig. 2. (X4-) Cranidium of the type specimen of the species. U. S. 

 National Museum, Catalogue No. 15442. 



The type specimen and cotypes are from a limestone of Lower 

 Cambrian age, (31c, 54 o) Ute Peak, Wasatch Range, Cache County, 

 Utah. 



Alokistocare althea Walcott 184 



Fig. 3. (X3-) Cast of cranidium in fine-grained sandstone. U. S. 

 National Museum, Catalogue No. 61571. 

 30. (X2.) Matrix of a cranidium in fine-grained sandstone. 

 U. S. National Museum, Catalogue No. 61572. 

 The specimens illustrated are from locality 74, Middle Cam- 

 brian : Tapeats sandstone ; at head of Nunkoweap Valley, Grand 

 Canyon of the Colorado River, Arizona. 



4. (X2.) Cephalon and portion of thorax. U. S. National Mu- 

 seum, Catalogue No. 61573. 

 4a. (X2.) Entire dorsal shield with exception of free cheeks. 

 Both 4 and 4a are compressed in fine arenaceous shale. U. S. 

 National Museum, Catalogue No. 61574. 



The specimens represented by figs. 4 and 4a are from the Upper 

 Cambrian: (746) Bright Angel shale; Cameron trail. Grand Canyon 

 of the Colorado River, Arizona. 



Alokistocare ? labrosum Walcott 184 



Figs. 5, 5'. (X 3-) Dorsal view of the cast of the interior surface of a 



cranidium and outline of profile. U. S. National Museum, 



Catalogue No. 61575. 



50- (X3-) A small cranidium from which the test has been 



exfoliated. U. S. National Museum, Catalogue No. 61576. 



The specimens illustrated by figs. 5 and 5a are from the Middle 



Cambrian: (sf) limestone in Wolsey shale, II miles (17.6 km.j 



south of Neihart, Cascade County, Montana. 



