﻿1 170 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 12.'] 



Page 

 Upper Pogonip group (Rhysostrophia zone), 1 mile above the mouth of 

 Ikes Canyon, Toquima Range, Roberts Mountains (i°) Quadrangle, Nev. 



Plate 165 

 Taphrodonta 



A. Taphrodonta parallcla Cooper, new species 74 1 



(1) Brachial view, X I, of the holotype, 117562c; (2-6) respectively brachial, 

 pedicle, side, anterior, and posterior views, X 2, of the holotype; (13) posterior 

 of the holotype, X 6, showing cardinal process, pseudodeltidium, and apical fora- 

 men; (7) pedicle interior, X 3, showing peculiar teeth, muscle area, and pallial 

 marks, paratype, ii7562g; (8) same as preceding tilted to show fossettes in teeth 

 and short flaring dental plates, X 3', (9) same view as preceding, X 4, showing 

 dental plates, crural fossettes, and inner subperipheral thickenings; (10) deltidial 

 region of the preceding, X 5, showing pseudodeltidium and plates on inside of 

 teeth; (11) same as preceding, X 2, showing structures in perspective; (12) 

 another pedicle interior, tilted to show deposits on inside of teeth and delthyrium, 

 X 3, paratype, 117562b; (14) another pedicle interior, X 2, showing pallial 

 marks and muscle area, paratype, 117562b; (15) posterior of preceding tilted 

 to look into delthyrial cavity, X 4, showing slight median ridge at apex, deposits 

 inside teeth, and genital marking; (16) brachial interior, X I, paratype, H7562i ; 

 (17) same as preceding but X 2, showing anterior pallial markings, cardinal 

 process, and brachiophores ; (18) same view, X 4, showing cardinalia and pallial 

 markings in detail; (19) posterior view of the preceding, X 4, showing the nar- 

 row cardinal process and long brachiophores; (20, 21) another and more perfect 

 brachial interior, X 3 and X 2, showing the wide, elevated median region and 

 the pallial mark on each side of it, paratype, H7562f; (22) posterior of the 

 preceding, X 5, showing the cardinalia in greater detail. 



Upper Pogonip group (upper 30 feet), 1 mile above the entrance to Ikes 

 Canyon, Toquima Range, Roberts Mountains (i°) Quadrangle, Nev. 



Plate 166 

 Apatomorpha 



A. Apatomorpha pulchella (Raymond) 709 



(1-3) Pedicle, brachial, and side views of a complete specimen, X 2, hypotype, 

 110901b; (5) brachial view of another complete specimen, X I, hypotype, 

 110901a; (7, 8) pedicle interior impression and a plasticine replica prepared 

 from it, X 2, showing dental plates and pallial marks, hypotype, 110900a; 

 (10, 11) another pedicle impression and the replica of the interior prepared from 

 it, X 3, hypotype, 110900b; (12) another pedicle interior, X 3, showing a great 

 development of the pallial marks, hypotype, 110900c; (13) a fourth pedicle im- 

 pression, X 3, showing muscle and pallial marks, hypotype, iiocxwd; .(*4) im- 

 pression of the brachial valve, X 3, showing pallial marks and muscle scars, 

 hypotype, H0900e; (15) plasticine replica of the brachial interior, X 2, prepared 

 from hypotype, nogoof; (16) brachial impression, X 2, from which the previ- 

 ous view was prepared. 



Athens formation (base), roadside just east of intersection z\ miles south- 

 southeast of Riceville, Calhoun (T.V.A. 125-SW) Quadrangle, Tenn. 

 (4) Pedicle exterior, X 2, hypotype, 110895a; (6) exterior of the brachial valve, 

 X 2, hypotype, 110895c; (9) pedicle interior, X 3, hypotype, 110896a; (17, 18) 

 brachial interiors, X 2, hypotypes, 110896b, 110896c; (19) same as fig. 17 but 

 enlarged X 3 to show median ridge and pallial marks, hypotype, 110896b; (20) 



