PUGNAX 203 



Remarks. Several species from our Mississippian and Devonian faunas, 

 which possess internal structures of the rostral portion of the brachial 

 valve entirely like those of Camarotcechia and not at all agreeing with 

 the genotype of Pugnax, have been referred commonly to the genus 

 Pugnax. With the removal of these species to the new genus Pugnoides, the 

 genus Pugnax itself is left with very meager representation in our faunas, 

 and of the two species here recognized the typical internal characters 

 have been observed in only one. 



PUGNAX WOBTHENI (Hall) 

 Plate XXV, Figs. 37-42 



1856. Rhynchonella Wortheni Hall, Trans. Albany Inst., vol. 4, p. 11. 



1882. Camarophoria Wprtheni Whitfield, Bull. Am. Mus. Nat. Hist., 



vol. 1, p. 54, pi. 6, figs. 35-39. 



1883. Camarophoria (?) wortheni Hall, 12th Rep. Geol. Surv. Ind., p. 



334, pi. 29, figs. 35-39. 



1906. Camarophoria wortheni Beede, 30th Ann. Rep. Geol. Surv. Tnd., 

 p. 1305, pi. 22, figs. 35-39. 



Description. Shell small, subovate in outline, the length and breadth 

 subequal or the width greater than the length, the greatest width near 

 or anterior to the mid-length of the shell. The dimensions of two indi- 

 viduals, the smaller one a young example, are : length 7 mm. and 4.5 mm., 

 width 7.4 mm. and 4.5 mm., thickness 5.3 mm. and 2.9 mm. 



Pedicle valve gently convex in the umbonal region, flattened towards 

 the antero-lateral margins, and deeply sinuate in front, the edge of the 

 valve along the postero-lateral margins towards the beak is inflected 

 to form a narrow, pseudo-cardinal area; the sinus originates near the 

 middle of the valve, is rapidly depressed, and in adult shells is produced 

 in front as a linguiform extension whose surface lies at nearly a right 

 angle to the plane of the valve ; the beak is pointed, scarcely incurved 

 and is produced conspicuously beyond that of the opposite valve; the 

 plications originate near the middle of the shell, and become rapidly 

 stronger as they approach the margin, one or two rounded ones occupying 

 the bottom of the sinus and about two, rarely more, more subangular 

 ones occupying each lateral slope of the valve. Internally a pair of 

 diverging dental lamella extend a short distance forward from the 

 beak. 



O 



PIG. 14. A series of two cross-sections of the rostral portion of the shell of 

 Pugnax wortheni (X 2%), showing the dental lamellae of the pedicle valve 

 and the entire absence of lamellae in the brachial valve. 



