404 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 53 



DESCRIPTION OF PLATE 35 



PAGE 



Olenellus thompsoni (Hall) (See pis. 34 and 44) 336 



Fig. I. Dorsal shield from the type locality (25), at Parkers quarry. 

 Georgia, Vermont. Reduced to two-thirds of natural size. 

 This figure was published [Walcott, 1886, pi. 23, fig. i] with 

 a space between the glabella and marginal border. The gla- 

 bella is crushed down even with the surface of the cheeks and 

 the draftsman left out the line indicating the margin of the 

 anterior glabella lobe. The same is true of fig. i, pi. 22. 

 Figures 2 and g, pi. 17, represented the correct position of the 

 • glabella. U. S. National Museum, Catalogue No. iS4i8t'. 



2. A large crushed telson from locality (Sij), 2 miles northwest 



of the City of York, Pennsylvania. X i-5- U. S. National 

 Museum, Catalogue No. 568350. 



3. Hypostoma that occurs on the inside of a cephalon. Only the 



base of some of the postero-marginal spines can be seen and 

 the median support, if ever present, is now broken off. Lo- 

 cality (25), Parkers quarry, Georgia, Vermont. X 2. U. S. 

 National Museum, Catalogue No. 15418c. 



4. Top view of a convex cephalon from the calcareous sandstone at 



locality (250), near Swanton. Vermont. A restoration based 

 on the specimen represented by this figure was given by Wal- 

 cott, 1886, pi. 17, fig. 9. Natural size. U. S. National Museum, 

 Catalogue No. 154190. 



5 and 6. Two small cephalons from the Rome sandstone, locality 

 (46), west of Cleveland, Tennessee, in which the natural con- 

 vexity of the cephalon is preserved. This is outlined in 50. 

 U. S. National Museum, Catalogue Nos. 26983a and 26983??, 

 respectively. 



7 and ya. Top and side view (X 3) of a very convex hypostoma 

 from the same locality (46) as the specimens represented by 

 figs. 5 and 6. U. S. National Museum. Catalogue No. 26983c. 



Olcticllus thompsoni crassiinargiiiatus, new variety 340 



Fig. 8. A flattened cephalon formerly referred to Olenellus thowpsoni 

 Hall. Natural size. From locality (25), Parkers quarry, 

 Georgia, Vermont. U. S. National Museum, Catalogue No. 

 568360. 



Figure 8 is copied from Walcott, 1886, pi. 17, fig. i. 

 9 and 10. Cephalons from locality (Sq), 2 miles northwest of the 

 City of York, Pennsylvania. Natural size. U. S. National 

 Museum, Catalogue Nos. 56837a and 56837^, respectively. 



