PLATE XXKYL— Continued. 



Page. 

 Figs. 31 and 32. Psiloconcha minnesotbnsis, n. sp 531 



31. The right side of a cast of thejinterior, which has been shortened by pressure no 



less than is indicated by the outline restorations. 



32. Dorsal outlines of same. Middle Galena, near Pleasant Grove, Minnesota. 



Figs. 33 and 34. Endodesma cuneattim, n. sp 526 



Dorsal and lateral views of an excellent cast of the Interior. Middle Galena, 

 near Wykofl, Minnesota. 



Figs. 35 to 37. Endodesma compressum, n. sp , 529 



35 and 36. Dorsal and lateral views of a cast of a left valve. Middle Galena, near Wykofl, 

 Minnesota. 

 37. Sectional view across the shell a short distance behind the beaks, showing the 

 Inbending of the hinge plate. 



Fig. 38. Endodesma UNDOSUM, n. sp 529 



Cast of the interior of both valves. "Upper Buff " beds of the Trenton formation, 

 near Belolt, Wisconsin. Geol. Sur. Mus. Reg. No. 8344. 



Fig. 39. CUNEAMTA TBUNCATA, n. sp ., 622 



Cast of the interior of a right valve. Middle Galena, near Wykofl, Minnesota. 



Figs. 40 and 41. Cuneamya oblonga, n. sp 623 



Lateral and dorsal views of the specimen described. The imperfect posterior 

 end is restored in the figure. Upper Galena, Dixon, Illinois. 



Figs. 42 and 43. SPHENOLnjM paeallelum, n. sp '. 624 



42. Cast of the interior of a right valve. Imperfect at the anterior end, but otherwise 



in an excellent state of preservation. 



43. Cardinal view of the same, with the left valve restored in outline. "Lower 



Blue" beds of the Trenton formation. Mineral Point, Wisconsin. Geol. Sur. 

 Mus. Eeg. No. 8346. 



Figs. 44 and 45. Sphenolium stbiattjm, n. sp 624 



Lateral and dorsal views of a nearly complete cast of the interior. Middle 

 Galena, Goodhue county, Minnesota. 



Figs. 46 and 47. Khytimya sinuata, n. sp 619 



Lateral and dorsal views of an internal cast of a left valve. Middle Galena near 

 Wykofl, Minnesota. 



