84 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I39 



Page 

 and anterior views showing the cardinalia, X2, hypotype U.S.N.M. 

 549348b. 10, The same, X 4> showing the large inner hinge plates 

 covering the apical chamber and the small transverse cardinal 

 process. 



Recent, U. S. Fish Commission Station 2923, 522 fathoms, off 

 San Diego, California. 



B. Eohemithyris columns (Hedley) 32 



Figs. 15-26. 15-17, Respectively brachial, anterior, and side views of a 

 complete specimen showing the anterior costation and uniplicate ante- 

 rior commissure, X l t hypotype U.S.N.M. 333012b. 18, Enlargement, 

 X 2, of the beak of the preceding specimen showing the small sub- 

 mesothyrid foramen and conjunct deltidial plates. 19, 20, Two views 

 of the interior of a pedicle valve, X 2, one in full view, the other 

 anteriorly tilted to show the minute dental plates, small genital areas, 

 and pallial sinuses, hypotype U.S.N.M. 333012a. 21, Apical part of the 

 preceding specimen showing beak, foramen, and conjunct deltidial 

 plates, X 4- 22, 23, Full view and slightly tilted view of the brachial 

 valve of the preceding specimen showing the cardinalia, pallial sinuses, 

 and genital areas, X 2. 24, 25, Partial side and full views of the cardi- 

 nalia showing the distally serrate, falcifer crus, corrugated sockets, 

 and thickening over the crural bases, X 4- 26, Posterior part of the 

 preceding tilted to show the concave ends of the crura, the small 

 genital areas, and the interior thickening, X 4- 



Recent, 1 15-135 fathoms, off Gabo Island, Victoria, Australia. 



Plate 16 

 Compsothyris 



A. Compsothyris racovitzae ( Joubin) 56 



Figs. 1-17. 1-4, Respectively anterior, dorsal, ventral, and side views of a 

 complete individual, showing faintly uniplicate commissure, X i| hypo- 

 type U.S.N.M. 549343. 5, Dorsal view of the preceding specimen 

 showing fine closely crowded costellae, X 2. 6, 7, Interior of the 

 pedicle valve of the same specimen, X 2, showing small foramen and 

 small dental plates. 8, Beak of the preceding valve, X 4, showing 

 small corrugated teeth and small disjunct deltidial plates. 9-1 1, 

 Respectively full, slightly tilted, and strongly tilted views of the 

 brachial interior of the same specimen showing cardinalia, median 

 septum, and muscle scars, X 2. 12, Same brachial interior tilted to 

 show the socket ridges and distally serrate spinulifer crura, X 4- 

 13-15, Three views of the cardinalia variously tilted to show socket 

 ridges, narrow outer hinge plates, and crura, X 4- 16, Same brachial 

 valve strongly tilted to show junction of crural supporting plates with 

 median septum, X 4- I7» Exterior of the pedicle valve, X 6, showing 

 the very fine radial costellae. 



Recent, British Antarctic Expedition 1910, Station 316 of Terra 

 Nova, 190 to 250 fathoms, 30.5° F., off Glacier Tongue, 8 miles north 

 of Hut Point, McMurdo Sound, Antarctic. 



