PUGNOIDES 



193 



Remarks. This genus approaches more closely to Camarotcechia than 

 any of those here considered, having camarotcechoid interiors, although 

 the genotype has usually been included in Pugnax, in which no median 

 septum or crural cavity is developed in the rostral portion of the brachial 

 valve. The members of this genus agree with Camarotcechia in general 

 size, and form, as well as in internal characters, being distinguished from 

 that genus by the obsolescence of the plications towards the beak, in which 

 character they are like Pugnax. 



PUGNOIDES OTTUMWA (White) 

 Plate XXV, Figs. 7-17 



1862. Rhynchonella Ottumwa White, Proc. Bost. Soc. Nat. Hist., vol. 9, 



p. 23. 

 1880. Rhynchonella ottumwa White, Cont. to Inv. Pal., No. 8, p. 165, 



pi. 41, figs. 5a-e. 



1894. Rhynchonella ottumwa Keyes, Mo. Geol. Surv., vol. 5, p. 103. 



1895. Pugnax Ottumwa Hall and Clarke, Pal. N. Y., vol. 8, pt. 2, pi. 60, 



figs. 23-26. 



1910. Pugnoides ottumwa Weller, Bull. Geol. Soc. Am., vol. 21, p. 512, 

 fig. 13. 



Description. Shell below medium size, suboval to subpentagonal in 

 outline, usually wider than long, the greatest width usually anterior to 

 the mid-length of the shell. The dimensions of two individuals are: 

 length 12 mm. and 10.7 mm., width 12.5 mm. and 11.3 mm., thickness 8 

 mm. and 6.3 mm. 



Pedicle valve with rather long, nearly straight postero-lateral margins 

 which meet at the beak in an acute angle, the lateral and anterior mar- 

 gins rounded, the surface convex in the umbonal region, curving abruptly 

 to the postero-lateral margins, less abruptly to the anterior margin and 

 only gently convex or nearly straight to the antero-lateral margins ; along 







G H | j K 



FIG. 9. A series of eleven cross-sections of the rostral portion of the shell of 

 Pugnoides ottumwa (X 2^/2), showing the dental lamellae of the pedicle valve 

 and the median septum, crural cavity and crura of the brachial valve. 



the postero-lateral margins towards the beak, the edge of the valve is ab- 

 ruptly inflected to form a sort of false cardinal area ; mesial sinus obso- 



7 



