PLATE IX. 



Fig. 2. Azygoias side. 1 opposite, 3 top, 4 base, 6 vertical section, showing pores at 

 " a," of Hydreioyiocriniis depressus, Troost (Wachsrauth non Weth- 

 erby), 325 



Fig. 7. Azygous side, 8 opposite, 9 top, 10 base, 11 var. (?) of H. armiger. Meek and 

 Worthen (Wachsmuth nonWetherby), 328 



Fig. 5. Species of Hydreionocrimis, probably new. 



Fig. 12. Azygous, 13 opposite side of P. Mllleri, 330 



All sjjeciraens in Prof. Wetherby's collection. 



