OLENELLUS AND OTHER GENERA OF MESONACID.E 4O9 



Olenellus fremonti, new species (continued) : 



313^). Associated fragments of other cephalons show the 

 genal spines located in the same relative positions as those 

 shown by figs. 10 to 13 from locality (51), Prospect Peak, 

 Nevada. U. S. National Museum, Catalogue No. 56819^. 



Figure 9 is copied from Walcott, 1886, pi. 20, fig. if, where 

 it is labeled Olenellus gilberti. 



This specimen is redrawn (X 6) on pi. 41, fig. 8. 



ID. Cephalon from locality (52) in the Eureka District, Nevada, 

 that is very m.uch like fig. 9. Natural size. U. S. National 

 Museum. Catalogue No. 56819/^. 



II, 12, and 13. Outlines of specimens of the cephalon with the genal 

 spines and intergenal angles more and more like the normal 

 type of cephalon as shown by figs. 7 and 14. The eyes are 

 short and connected with the glabella by an occular ridge. 

 Natural size. Locality (52), Prospect Mountain, Eureka Dis- 

 trict, Nevada. U. S. National Museum, Catalogue Nos. 

 568i9g, 56819A, and 568191, respectively. 



Figures 10, 11, 12, and 13 are copied from Walcott, 1884, pi. 

 21, figs. 2, 4, 3, and 6, respectively, where the forms are labeled 

 Olenellus hoivelli. 



14. A cephalon with short eye lobes, occular ridges, and normal 



genal angles. Natural size. Locality (52), Prospect Mount- 

 ain. Eureka District, Nevada. U. S. National Museum, Cata- 

 logue No. 56819;'. 



Figure 14 is copied from Walcott, 1884, pi. 9, fig. 15, where 

 it is labeled Olenellus howelli. 



15. A cephalon without distinct occular ridge connecting the glabella 



and eye lobes. Natural size. Locality (52), Prospect Mount- 

 ain, Eureka District, Nevada. U. S. National Museum, Cata- 

 logue No. 56819^'. 



Figure 15 is copied from Walcott, 18S4, pi. 21, fig. 5, where 

 it is labeled Olenellus hoivelli. 



16. A cephalon 9 mm. in length that has the outline shown by fig. 



12 but with the ej^es close to the glabella. Natural size. 

 Locality (52), Prospect Mountain, Eureka District, Nevada. 

 U. S. National Museum, Catalogue No. 56819/. 



Figure 16 is copied from Walcott, 1S84, pi. 9, fig. 15a, where 

 it is labeled Olenellus hoivelli. 



17. A narrow, convex, cephalon with elongate eye lobes of the 



adult type and with genal angles advanced as in small 

 cephalons shown by figs. 11 and 12. Natural size. Locality 

 (51), Prospect Mountain, Eureka District, Nevada. U. S. Na- 

 tional Museum, Catalogue No. 568i9;h. 



18. Cephalon with the genal spine on the left side in advance of 



that on the right side. Natural size. Locality (52), Eureka 

 District, Nevada. U. S. National Museum, Catalogue No. 

 568 I 9«. 



