viii List of Figlkks in Text. 



Eiinella liiukUcn Hall I'art of loop of adult s])ecimen . . -135 



" " Centronelliform stage of loop . . . . 135 



" " " Side view of specimen in above figure . . 135 



Cyriina Iiaiiiiltoiifiisis \\-c\\\. Outline of smallest specimen . -136 



" *' " Profile of larger specimen . . .136 



" " " Outline of " " . . .136 



" " " Individual, showing rapid change in 



relative convexity of valves . • .136 

 " " " Anterior, cardinal, and dorsal views . 137 



" " Section through ventral valve . -137 



Spirifcr niuci'onatiis Conrad. Outline of protegulum and shell in 



nepionic stage .... 141 



" " " Ventral vahe . . . . . 141 



" " '' Ventral valve, six plications . . 141 



" (V7.v/^/^.s' (Hisinger). Dorsal and cardinal views of a specimen 



" " " from Waldron, Ind. . . . 146 



" " " Dorsal and \'entral views of a specimen 



from Gotland , . . . .146 



Bacna callosa Hay. Diagram of portion of carapace . . -179 



" " " " plastron . . . . . ,180 



Batliyurus angeluii Billings. Outline drawing of type specimen . 336 



IllcEHus vindex VixViwigs. Dorsal and anterior \iews . . . . 353 



G/ap/uinis pustu/atus \Na.\co\.\.. Outline of young specimen . . 361 



SpJicerexocJins parvus Billings ........ 366 



Cerajirus ponipiliiis " . . . . . . . . 366 



Platynwtopiis niuigaiioisis Billings ....... 366 



Roiioph'urides cauadoisis " ....... 366 



Reproductions of Billings' original figures in \'ol. I of Paleozoic Fossils 



of Canada. .......... 366 



PseudospIicerexocJius vulcanits Billings. Rejiroductions of Billings' 



figures . . . 368 



" " Billings var. billingsi. Reproductions 



from Billings' figures . . . 368 



Goniopholis giliuorci. Tooth ; outline of section at base ; outline of 



section at middle of crown . . . 433 



Cambanis {Procainbanis) lui/Iiains ni. Male copulatory organ of right 



side seen from outside . 440 

 " " " Male copulatory organ of right 



side seen from inside . 440 

 " " " Annulus ventralis of female . 440 



Mastodon amcricanus Kerr. Posterior, anterior, and external lateral 



views . ..... 464 



