22,2 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 57 



DESCRIPTION OF PLATE 31 



PAGE 



Hymenocaris perfecta Walcott 183 



P'lG. I. (X2.) Side view of the right valve, showing the form of the 

 valve, abdomen, and numerous appendages. Adductor muscle 

 scar (ad), intestine (i), thoracic legs (thl), gills (br). U. 

 S.- National Museum, Catalogue No. 57703. 

 2. (Xi-5-) Dorsal view of a specimen from which the test has 

 been exfoliated. This shows the antenna (a), adductor 

 muscle scars (ad), intestine (i), and traces of the basal 

 joints of the legs. U. S. National Museum, Catalogue No. 



57704- 



3, 4, and 5. (X2.) Illustrations of the posterior end of the abdo- 

 men with cercopods. U. S. National Museum, Catalogue 

 Nos. 57705, 57706, and 57707. 



6. Specimen in upper left hand corner of figure. (Natural 

 size.) Dorsal view of a crushed speicmen showing the cara- 

 pace, abdomen, and cercopods. U. S. National Museum, Cat- 

 logue No. 57708. 



Leanchoilia superlata Walcott 170 



Fig. 6. Lower specimen. (Natural size.) Side view of the type and 

 only specimen known of the species and genus. U. S. Na- 

 tional Museum, Catalogue No. 57709. 



All of the specimens illustrated on Plate 31 are from locality (35k) Middle 

 Cambrian : Burgess shale member of the Stephen formation, on the west slope 

 of the ridge between Mount Field and Wapta Peak, one mile (1.6 km.) north- 

 east of Burgess Pass, above Field, British Columbia. 



