XXVI 



SYNOPSIS OF GENERA. 



L859. 



is.;,; 



1-71. 



1876. 

 1877. 

 L878. 

 L878 

 1878. 

 1-7.'. 

 1-71'. 



1883. 



1884. 



1884 



1885. 



L885. 



1885. 



1887. 

 1888. 

 1888. 



Pal. V V., vol. iii. 

 . McCoy. Synops. Sil. Poss. Ireland. 



Dev. and Silur. Foss., Square Lake, Maine. 

 ( '.-,i. Silur. Foss. A.nticosti. 

 . p \ !:.i m k. Beitr. v zur Harzgeb. 

 Hall. Twentieth Rept. N. Y. State Cab. Nat. Itist. 

 iskissent. Kssai sin- l:i g6ologie de hi Manche. 

 . Babraxde. Syst. Ml. Bohfime. vol. i. Suppl. 

 Gosselet. Bull. de l'Acad. roy. de Belgique. 

 \ts, Tkomelin and Lebescoste. Bull. Soc. g6ol. de Prance, 

 s, Rcemer. Lethaea palseozoica. 



I [] 1 1\ and Grasset. Assoc, francais Avanc. Si 

 .Whitfield, inn. Rept. Geol. Surv. Wisconsin. 



Expl. Carte g6ologique de France, Atlas. 

 . Katser. Fauna a-lt. Devon. Abl. d. Harzes. 

 . Katser. Zeitschr. der deutsch. geol. Gesellschaft. 

 , S i >;:. stiuiiin an Hj postomen, i. 

 ■ .-■. Whitfield. Geol. Wisconsin, vol. iv. 

 Novak. Zur Kenntn. bobm. Tiilob. 

 Neues Jahrb. fiir Min. 

 Studien an Hypostomen, ii. 

 Hull. < 1 * ■ la Soc. d'Etudes Scientif. d'Angers. 

 Ann. Soc. geol. du Nord. 

 Kalke von Waldgirmes. 

 Handb. d. Palaeontologie. 

 Ann. Soc. geol. dn Nord. 

 rnychew. M6m.Comit6.g6ol. 

 Brontes, Frech. Zeitschr. der deutsch. geol. Gesellschaft. 



Pehecku. Zcit.scln-. dm- ili'utsch. geol. Gesellschaft. 



, I ! IRKE. 



'■ 



\ts, CEhlert. 

 Bronti us, B 



(8, M U'KKK. 

 0S, ZlTTEL. 



Diagnosis. Body broadly oval. Cephalon semi- 

 circular, with sharp, often somewhat produced genal 

 angles. Glabella closely appressed to the cheeks, 

 broad anteriorly and extending to the frontal mar- 

 gin. Lateral furrows indistinct or obsolete. The 

 facial sutures begin on the posterior margin, and in 

 trout of the eyes run nearly parallel to the margin of the glabella, being con- 

 tinuous on the frontal margin. Eyes lunate, homocorneal, and situated some- 

 what posteriorly. Thorax slightly larger than the cephalon, and composed 

 of ten segments, which upon the pleurae are simple and sharply pointed. 

 Pygidium very large, depressed-convex, paraholic in outline, with a very short 

 sub-triangular axis. The pleurae each hear seven or eight simple ribs, arranged 

 on each side of a larger median simple or compound rib. 



