2IO SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 57 



DESCRIPTION OF PLATE 25 



Legend : 



c = carapace. m=third appendage = mandible. 



x=posteriorspines or lobe>; of carapace. m'=fourth appendage = maxillula. 



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

 lb=labrum. i = inte5tine or alimentary canal. 



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

 ab=abdomen. l = setiferous jointed exopodite. 



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

 a"=antenn8e. 



PAGE 



Marrella splendens Walcott (see pi. 26) 193 



Fig. I. (X4-) Dorsal view of a crushed specimen in which the junc- 

 ture of the antennules ? (a') and the carapace is clearly 

 shown. U. S. National Museum, Catalogue No. 57664. 



2. (X4-) Dorsal view illustrating the segments of the body, cara- 



pace and its great posterior spines. U. S. National Museum, 

 Catalogue No. 57665. 



3. (X4.) Dorsal view of a partly exfoliated specimen show- 



ing the antennae (a"), a feather-like maxillula, and one of 

 the remarkable setiferous exopodites. U. S. National Mu- 

 seum, Catalogue No. 57666. 



4. (X3.) A specimen crushed sideways so as to force the eye (e) 



out prominently on the left side. U. S. National Museum, 

 Catalogue No. 57667. 



5- (X3-) A sliglitly distorted specimen illustrated to show the 

 eyes (e). U. S. National Museum, Catalogue No. 5766S. 



6. (X4-) Dorsal view of a speciinen showing the setiferous 

 exopodites as they lie one on the other with the setae point- 

 ing forward and outward. U. S. National Museum, Cat- 

 alogue No. 57669. 



All of the specimens illustrated on Plate 25 are from locality (3Sk) 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. 



I 



