148 ANNALS NEW YORK ACADEMY OF SCIENCES 



nodes, the larger and more prominent along the ventrolateral shoulder, the 

 smaller and less prominent on the umbilical shoulder. Both these loci are 

 well denned and more or less strongly angular during the periods of adoles- 

 cence and maturity. 



The sculpture at maturity consists of very obscure incremental lines which 

 tend to become sharp lira? on the tubercles, and they show a deep sinus over 

 the ventral surface. 



The septa are not well exhibited by my specimens, though this is a fairly 

 common fossil in the Wewoka fauna. In a mature example, they are 3.5 mm. 

 apart along the middle of the venter, and the suture is very nearly straight, 

 depressed, however, into a shallow ventral lobe and with very obscure saddles 

 on the ventrolateral shoulders. In this region, the suture is liable to be more 

 or less deflected by the pila?, which are not developed exactly with regard to 

 the septa. In some cases the nodes occur on the septa ; in others between them, 

 and there are about three nodes to four septa. In a young specimen which 

 probably belongs to this species, there is a suggestion of a very small, pointed 

 dorsal lobe, somewhat as in the genus Endolohus. The siphuncle appears to be 

 central or somewhat below the center. 



I know of no American nautiloid which this species so much resembles 

 as that which Hyatt described as Temnocheilus crassum. The whorl sec- 

 tion of perelegans is more transverse and somewhat differently shaped, 

 with distinct umbilical shoulders. The pilas have nodes at both ends in- 

 stead of near the ventral surface only, and at maturity they disappear, 

 leaving only the two rows of nodes. 



Horizon and locality: Wewoka formation; Wewoka quadrangle, Coal- 

 gate quadrangle, Okla. 



Metacoceras sculptile sp. now 



Shell rather large, attaining a diameter of 67 mm., discoidal, with large 

 umbilici, 31 mm. across at the diameter named. 



Whorl section modified hexagonal, consisting of a relatively narrow ventral 

 surface, two broad lateral surfaces, two umbilical zones and an impressed 

 zone, all narrow. The ventrolateral and umbilical angles are distinct and 

 only slightly rounded. The ventral surface is marked by two shallow sulci 

 situated close to the margins, on either side of which the shell rises slightly 

 into a gently convex median portion and gently elevated ventrolateral angles. 

 The sides are flattened and slope distinctly outward from above to the um- 

 bilical shoulder. There, with an abrupt subangular change of direction, they 

 are withdrawn inward and somewhat downward to a rather deeply concave 

 impressed zone. Greatest height of the final volution 31 mm. ; greatest width 

 (at the umbilical shoulder) 25 mm. ; width of ventral surface 15 mm. ; width of 

 lateral surface 24 mm. ; width of umbilical zone 8.5 mm. ; width of impressed 

 zone 9.5 mm. 



The sculpture seems to consist of fine, even stria?, which follow the lines of 

 growth, leaving between them sharp, strong, angular lira?. This sculpture, 

 however, is more or less concealed in our specimens by a thin, even, super- 



