ART. 12 CLASSIFICATION OF CONODONTS — ULRICH AND BASSLER 45 



pointed end, dividing the plate into tAvo lateral, subequal areas. The 

 carina is also indicated by a corresponding ridge on the underside. 

 On the upper surface the summit of the carina carries a row of 

 closely approximated nodes and the depressed sides of the plate are 

 variously ornamented with nodose ridges. The underside is smooth 

 or Avith fine concentric lines. 



POLYGNATHUS RIMULATUS, new species 



Plate 1, figs. 8, 9 



This is a much smaller species than the genotype P. permatus, 

 which it resembles in general aspect but differs structurally in the 

 fact that the edge of the lanceolate plate is definitely raised in a 

 continuous minutely nodose rim. The depressed spaces between this 

 rim and the central crest are also smaller and on the whole give 

 much less the appearance of outwardly enlarging rows of nodes 

 characterizing that species. 



Occurrence. — Devonian (Rhinestreet) : Shaleton, N. Y. 



Cotypes.— Cat No. 11302, U.S.N.M. 



POLYGNATHUS PENNATULUS, new species 

 Plate 7, fig. 8 ; Plate 9, figs. 24, 25 



Our views illustrate the top, profile, and cross section showing 

 crest and concave lateral areas wdth margins elevated nearly to level 

 of crest. The outline is lanceolate, although not quite equilateral, 

 but the species is distinguished from others of similar form by the 

 surface markings, the crest having a double row of tubercles and 

 the lateral areas covered by pinnately arranged similar tubercles. 



Occurrence. — Mississippian (Hardin sandstone) : Mount Pleasant, 

 Tenn. 



Holotype.—C2it. No. 10996, U.S.N.M. 



POLYGNATHUS DELICATULUS, new species 



Plate 7, figs. 9, 10 



Closely related to P. pennatulus but markings more delicate and 

 arranged more transversely. These markings take the form of 

 numerous parallel striations arranged nearly at right angles to the 

 prominent median crest. 



Occut-rence. — Mississippian (Hardin sandstone) : Mount Pleasant, 

 Tenn. 



Cotypes.—C-Ai. No. 10994, U.S.N.M. 



