40 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 57 



DESCRIPTION OF PLATE 7 



PAGE 



Sidneyia inexpectans Walcott 24 



Fig. I. Fragment of the ventral side of a small dorsal shield. X 2. 

 This shows the position of the leaf-like branchiae and bran- 

 chial fringes. U. S. National Museum, Catalogue No. 57498. 



Beltina danai Walcott 21 



Fig. 2. Fragment of the cephalo-thorax, showing the posterior margin, 

 a low, broad furrow, and in advance of that, irregular, trans- 

 verse ridges and scattered tubercles. Natural size. U. S. 

 National Museum, Catalogue No. 57501. 

 2a. An untouched photograph of the specimen represented by 

 fig. 2. 



3. An abdominal segment compressed in the siliceous shale that 



preserves more or less of the tuberculated surface. Natural 

 size. U. S. National Museum, Catalogue No. 57502. 



The specimens represented by figs. 2 and 3 are from local- 

 ity (i4z) Algonkian: near the head of Johnson Creek on 

 the Continental Divide west of Pincher Post Office, Alberta, 

 Canada. 



4. A large abdominal segment preserving a portion of the original 



convexity and tuberculated surface. Natural size. U. S. 

 National Museum, Catalogue No. 57503. 



The specimen represented by fig. 4 is from locality (i4y) 

 Algonkian : Altyn limestone ; southeastern base of Appekuny 

 mountain, opposite the inouth of Canyon Creek, in Swift 

 Current Creek valley, at second gap from eastern end of 

 mountain, near Altyn, Montana. 



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