FOSSIL SPONGES. 
For remarks on Sponge remains in the Middle Secondary Rocks of 
Yorkshire, cf. W. H. Hudleston, in P. Geol. Ass. v. pp. 443, 494. 
Quenstedt, F. a. Petrefactenkunde Deutschlands. v. pt. 1. Die 
Schwamme. Leipzig : 1878, with Atlas of 28 folio plates. 
A number of fossil species are described. The plates give the outward 
form, with much of the anatomy, and often the microscopical structure, 
of a great number of these. 
