jiuT. 1-' Cl.ASSIFICATlON OF CONODONTS ULEICH AND BASSLER 43 



Genus PACHYSOMIA Smith, 1907 



Text fig. 4 (p. IG) 



" Beam thick and curving, one extremity with a knoblike termi- 

 nation, other end sharp" (Smith, 1907). This type of structure 

 hiis not been found in American strata. 



Genotype. — Pachysomia wanlocJiensis Smith, 1907. Ordovician 

 of Scotland. 



Genus VALENTIA Smith, 1907 



Text fig. 17 (p. 16) 



"From a deep, thin plate a few long slender teeth spring" (Smith, 

 1907). Based apparently upon a fragmentary^ specimen. 



Genotype. — Valentia morrochenshi Smith, 1907. Ordovician of 

 Scotland. 



Genus PRIONOGNATHUS Pander, 1856 



Text figs. IS, 19 (p. 16) 



As our copies of the original illustrations show it is possible that 

 this genus does not belong to the conodonts. 



Genotype.— Prlonognathns hrnndtii Pander, 1856. Silurian, Island 

 of Oesel. 



Family POLYGNATHIDAE, new family 



Plates with a high denticulated median or lateral crest which is 

 often extended stalklike from one end. 



Polygnathus (Hinde) Bryant, 1921, AncyrodeJla^ new genus, 

 and Palmatolepis, new genus, are referred to this family without 

 question but Gnathodvs Pander, 1856, P anderodella., new genus, and 

 Ctenognathus Pander, 1856, are placed here provisionally. 



Genus POLYGNATHUS (Hinde) Bryant, 1921 



Polygnathus was founded by Hinde upon a group of plates and 

 teeth occurring associated on the same slab of Rhinestreet shale from 

 western New York which he believed to represent the remains of a 

 single animal. In this assemblage no less than five genera as now 

 understood Avere represented, and it would have been better to have 

 discarded the genus. Since Bryant has redefined the genus and 

 selected a genotype, P. pennatus, which he says is represented in 

 Hinde's type assemblage of P. dvhius in the edge view of the com- 

 mon Genundewa species the genus may be recognized in this re- 

 stricted sense. Based upon species in accord with the genotype 

 selected by Bryant, Polygnathus may be defined as follows: 



Plate subsymmetrically lanceolate, traversed by a high median 

 carina extending stalklike from the broader end and reaching, 

 althougli diminishing giadually in height, to the opposite usually 



