Plate XVI. 



Palseostoma mirabile Gray. 

 P. 37, 4o, -A 



Fig. 184. A liiilf-s;i-o\vn specimen, dorsal view. 



Pig. 185. The same, ventral view. 



Fig. 186. The same, side view. 



Fig. 187. The peristomal region, with the pfiitangiilar stoma, the valves, the rtrst spherids etc. 



Fig. 188. The peristome, with the valves, from the inside. 



Fig. 189. The valves, from the outside. 



Fig. 190. The calyx with the two sexual pores. 



Fig. 191. The excretory opening with its valves. 



Fig. 192. A phyllodean pedicel. 



Fig. 193. Another phyllodean pedicel, both sliowiiig what seems to be a central protuberance. 



Fig. 194. The disk of a frontal pedicel, p. .^.'!. 



Fig. 195. Spicules from a pediceilar tube. 



Fig. 196. A tubercle. 



