420 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 53 



DESCRIPTION OF PLATE 43 



PAGE 



Liiniilus polyl^hcniiis 239 



Fig. I. Inner surface of the test of the eye of adult L'inuhis showing 

 cones with a minute opening at the apex. X 6. The sharp 

 apex of the cones is shown near the edges where they are seen 

 more in profile. 



2. Exterior of the same eye of which the interior is shown by 



fig. I. The pits and ridges of the test between them is finely 

 shown. X 7- 



3. A portion of the outer surface of the eye represented by fig. 2 



enlarged to 25 diameters. 



4. Enlargement of the outer surface of the eye on a cephalon 



7 mm. in length. X 25. This represents the eye in a younger 

 stage of growth than that represented by figs. 2 and 3 where 

 the pits have ridges between them that are flatter and broader 

 and more like those of Olcucllns gUbcrti as shown by fig. 5. 



Olenellus gilbcrti Meek (See pi. 36) 239 



Fig. 5. Enlargement of the visual surface, palpebral lobe, and portion 

 of the glabella, X 75. of the cephalon represented by fig. 6. 

 There are 42 openings on the portion of the visual surface 

 exposed. These openings and the ridges separating them are 

 similar in appearance to those of the eye of young speci- 

 mens of Liniuhis polyphcitnts as shown by fig. 4. 

 6. A small cephalon. X 50. The right eye of this is shown in 



fig. 5- 



The specimen represented by figs. 5 and 6 is from the lime- 

 stone at (35/), Ptarmigan Pass, Alberta (see pi. 36, figs. 11- 

 16). U. S. National Museum,* Catalogue No. 56828/^. 



