36 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 57 



DESCRIPTION OF PLATE 5 



PAGE 



Sidneyia inexpectans Walcott 24 



Fig. I. The third, fourth, and fifth appendages of the cephalo-thorax, 

 showing the gnathobases and something of the proportions of 

 the appendages. X 3- U. S. National Museum, Catalogue 

 No. 57494. 



2. A small, nearly entire dorsal shield flattened and broken by 



compression in the shale. The position of the visceral cavity 

 beneath the abdomen is faintly indicated through the thin 

 test. Natural size. U. S. National Museum, Catalogue No. 

 57495- 



3. A large epistoma attached to the frontal rim of the cephalo- 



thorax and crowfded back over the two anterior segments 

 of the abdomen. Natural size. U. S. National Museum, 

 Catalogue No. 57496. 



Amiella ornata Walcott 2y 



Fig. 4. Portion of a broken dorsal shield, showing parts of several 

 abdominal segments which have been pushed one over the 

 other. X 2. U. S. National Museum, Catalogue No. 57499- 



