Fig. 36.— Thoracic ribs of Antrodemus valens Leidy, No. 

 8367 U.S.N. M. J NAT. size. Viewed from the front. 

 All of the right side. A, First (?) thoracic rib. B, 



FOURTH thoracic RIB; C, SEVENTH THORACIC RIB; D, NINTH 

 thoracic rib. I. p. LATERAL PROCESS. 



