[dawson] 



FOSSIL SPONGES 



Trans. ISiifl. Skc. IV.— Pj.atb I. 



Fig. 8. 



Fig. 2. 



Fig. 4. 



Fig. l.—Protospongla tetranema. 



Fig. 2.— P. mononema. 



Fig. .3.— Do Showing oscuhan, partly broken away. 



Fig. A.— P. tetranemci. Seen in section with root. (All natural size.) 



123 



