OLENELLUS AND OTHER GENERA OF MESONACID^ 



INDEX 



Note. — The first reference to each of the species described in this paper gives 

 the page upon which the description begins and the figure references. Refer- 

 ences to the description of certain parts or features of a species arc only given 

 in the index if the description occurs outside of the detailed description of the 

 species. For instance : the description of the pygidium of a certain species will 

 be found in the description of that species and there will be no specific reference 

 in the index to the pygidium unless it is described or discussed at some other 

 point in the paper. 



The list on pages 351-371 ftiay be regarded as a completely cross-referenced 

 index to the synonymy in this paper, and only the actual references as they 

 occur in the synonymy will be found in this index. 



PAGE 



Acknowledgments 234 



Acrotreta sagittalis taconica, mentioned 318 



adamsi, see Orthothcca. 



Agassiz, Alexander, bibliographic reference 372 



on the habits of young Liinultts 241 



Agnostus, intergenal spines in 237 



Agnostus graniilatus Barrande, intergenal spines of 237 



Agnostus rex Barrande, intergenal spines of 237 



Agraulos, mentioned 318, 348 



Alabama, young cephalon of Pccdcumias transitans from described. .. .308, 309 



Albcrtella, a descendant of the Mesonacidae 254 



Algonkian sediments, freshwater origin of 252 



aincricaniis, see Hyolithcs. 



Andrarum, fossils from 290 



Annelidian-like ancestor, development of Mesonacidse from 249 



Anse au Loup, see L'Anse an Loup. 



Anterior border segment defined 238 



Anterior glabellar lobe in the Mesonacid.-e discussed 242 



A pus, eye of compared with that of Li))iulus 239 



ArchcEOchyathusf, mentioned 300, 315, 323 



argentus, see Olenellus. 



Arionellus , mentioned 290 



Arizona, fresh water origin of Algonkian sediments in 252 



arinatus, see Olenelloides. 

 asaphoidcs, see ElUptocepJiala. 



Asaphns, eye of compared with that of LiDiulus 239 



Barrande, J., bibliographic references 372 



Barrandia Hall, in synonymy > 261, 311 



McCoy, in synonymy 311 



thompsoni Hall, in synonymy 336, 2>i7 



vennontana Hall, in synonymy 265, 305 



Barrel Spring section, fossils from 296, 315, 320, 32^, 330 



