PLATE XXIIL 
Fig. 1. Sylkemus laiifrons Copo, natural size, seen from above. Tlio body behind the dorsal fin is broken 
off; la, the same from below. The body is distorted by pressure, so that the line of mucous 
pores of the right side is visible iu this figure. Page 27. 
Figs. 2-9. ITnios from the Trias of the Galliuas, obtained with the Saurians figured on Plate I, and de¬ 
scribed by Mr. Meek iu the Annual Report of Lieutenant Wheeler for 1875, Appendix G 1, 
page 83. Natural size. 
Figs. 2, 2a. Unio cristonensis. Pago 9. 
Figs. 3, 3a, 4, 5. Unio criatoiwiisis. 
Figs. G, 6a. Unio gallinensis. Pago 9. 
Figs. 7, 7a. Unio terrwrnhno. Page 9. 
Figs. 8, 8a, 9, 9a. Unio of uudeteriniued species. 
Figs. 10-29. Cranial bones, vertebraj, and scales of the typical specimen of Clasfes aganus, natural size. 
Page 38. 
Figs. 10-14. Basioccipital bone and dorsal vertebrae, seen from below, with two iuterruptiou.s. 
Fig. 10a. Basioccipital bone, posterior view. 
Figs, lla, 12a. Posterior views of vertebrae 11 and 12. 
Figs. 12&, 136. Anterior views of vertebras 12 and 13. 
Figs. 15-20. Cranial bones, from above; a, from below; 6, edge or sutural view. 
Fig. 21. Fragment from scapular arch. 
Figs. 22-29. Scales of the same specimen ; a, inferior views; figs. 22-25 pierced by lateral line. 
Figs. 30-31. Scales and bone of Gar found together, natural size. 
Fig. 30. Portion of the dermal armor of the right side. 
Fig. 31. An opercular bone. 
