21.2 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 57 



DESCRIPTION OF PLATE 26 



Legend : 



c=carapace. m = third appendages mandible. 



x = posterior spines or lobes of carapace. m' = foiirth appendage = maxillula. 



e = eye. m" = fifth appendage=maxilla. 



Ib=labrum. i = intestine or alimentary can»l. 



th = thorax. thI = thoracic legs [endopodites]. 



ab=abdomen. l=seiiferous jointed exopodite. 



a' = antenniile ?. br=branchial lobes or gills [epipodites]. 

 a" = antenn9e. 



PAGE 



Marrella splendens Walcott (see pi. 25) 193 



Fig. I. (X3-) Dorsal view of a specimen showing the carapace with its 



great posterior spines or lobes and the large antennules?. U. 



S. National Museum, Catalogue No. 57670. 

 2. (X3-) Ventral view of a crushed specimen showing the 



labrum (hypostoma) nearly in its normal position. U. S. 



National Museum, Catalogue No. 57671. 

 3- (X3-) Dorsal view of a specimen showing intestinal canal, 



feather-like maxillula (m), and the long joints of the setifer- 



ous exopodites. U. S. National Museum, Catalogue No. 



57672. 

 4. (X4-) Ventral view of a specimen showing the large gill lobes 



(br) (epipodites). U. S. National Museum, Catalogue No. 



S7(>73- 

 5- (X3-) Dorsal view of a specimen that illustrates the relative 



position of the antennae, the mandible, maxillula, and maxilla. 



U. S. National Museum, Catalogue No. 57674. 

 6. (X4-) Ventral view of a specimen showing the thoracic legs 



(thl, endopodites) and the setiferous legs (1, exopodite). U. • 



S. National Museum, Catalogue No. 57675. 



All of the specimens illustrated on Plate 26 are from locality (35k) Middle 

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

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

 east of Burgess Pass, above Field, British Columbia. 



