PLATE XLV. 



Unless otherwise is stated, all the figures on this plate are magnified about twenty diameters. 



PAGE. 



Figs. 1 to 3. EURYCHILINA VENTROSA, n sp. or var 662 



1. Left valve, Imperfect at the extremities, yet preserving the essential characters 



of the species. Galena shales, Cannon Falls, Minnesota. 

 2 and 3. Lateral and posterior views of a perfect right valve, from the same locality. 



Figs. 4 to 6. EURYCHILINA (?) SYMMETRICA, n. sp 663 



(See also plate XLIV, figs. 57.) 



4 and 5. Side and end views of a valve, x 28, differing somewhat from the specimens 



figured on plate XLIV. Upper third of the Trenton shales, St. Paul, Minn. 

 6. Longitudinal section of same. 



Figs. 7 to 9. EURYCHILINA (?) SUB^EQUATA, n. sp 663 



Side view of a left valve, with vertical and longitudinal sections of same. Upper 

 third of the Trenton shales, St. Paul, Minnesota. 



Figs. 10 to 12. APARCHITES FIMBKIATUS Ulrich 645 



Side, ventral and posterior views of a right valve. Hudson Eiver group, Spring 

 Valley, Minnesota. 



Figs. 13 to 15. LEPERDITELLA T0MIDA Ulrich 637 



Side, dorsal, and posterior views of a typical right valve of this species, x 15, from 

 the Birdseye limestone at High Bridge, Kentucky. Introduced for comparison 

 with L. canalis and L. persimilis, figured on plate XLIII. 



Figs. 16 to 18. APARCHITES MILLEPUNCTATUS Ulrich 645 



Ventral, anterior, and side views of a right valve. Surface punctation omitted 

 except on the antero-dorsal fourth of fig. 18. Trenton shales, Fountain, Minn. 



Figs. 19 and 20. LEPEKDITELLA DORSICORNIS Ulrich 639 



19. A left valve, x 15. Hudson Eiver group, Savannah, Illinois. 

 20 and 20a. Outlines of same in dorsal and anterior views. 



Figs. 21 to 23. APARCHITES GRANILABIATA Ulrich 644 



Posterior, side, and ventral views of a left valve. The minute surface granules 

 are omitted except on a small space of fig. 22. Upper third of the Trenton 

 shales. St. Paul, Minnesota. 



Figs. 24 to 26. LEPERDITELLA GERMANA Ulrich 638 



Outlines of a left valve in anterior, side, and ventral views, x 15. Lower Tren- 

 ton limestone, Mineral Point, Wisconsin. 



Figs. 28 f/o 30. PRIMITIELLA FILLMORENSIS, n. sp 649 



Three views of a right valve of this small species. Trenton shales, Fountain, 

 Minnesota. 



Fig. 31. PRIMITIA MINCTI88IMA, n. sp 651 



A left valve. Trenton shales, Fountain, Minnesota. 



Figs. 27, 3233. SCHMIDTELLA INCOMPTA, n. Sp 642 



(See also plate XLIII, flgs. 39 11.) 



27. Interior of a left valve. Trenton shales, Fountain, Minnesota. 

 32 and 33. Side and anterior views of a right valve; from the same locality. 



Figs. 34 and 35. SCHMIDTELLA BREVIS, n. sp 642 



Side and anterior views of a left valve. Trenton shales, Fountain, Minnesota. 



Figs. 36 to 38. SCHMIDTELLA UMBONATA, n. sp 641 



36 and 37. Anterior and side views of a left valve (opposite valve restored). Upper third of 



Trenton shales, St. Paul. Minnesota. 

 38. View of the interior of a right valve, from the same locality. 



Figs. 39 to 42. SCHMIDTELLA SUBROTUNDA, n. sp 643 



Side and end views of a right and left valve. In both cases the opposite valve 

 has been restored. Lower third of the Trenton shales, Minneapolis, Minn. 



