THE PORIFERA AND PROTOZOA 329 



bryozoal deposits, for instance the Coralline Crag (Lower 

 Pliocene) of East Anglia. 



The Annelida (segmented worms) are for the most 

 soft-bodied and rarely preserved ; but one order, Tubicola, 

 is characterized by a fixed habit and the secretion of a 

 tube. These tubes may be nearly straight, regularly 

 curved, spiral or irregularly twisted. The curved tubes 

 might be confused with Dentalium, the irregular for an 

 uncoiled, and the spiral for an ordinary gastropod, and 

 there are cases where the proper placing of such a fossil 

 is still doubtful ; but in general there is a roughness and 

 want of regularity about annelid tubes that prevents 

 confusion between them and molluscan tests. 



Short Bibliography. 



PORIFERA. 



HINDE, G. J. (i) British Museum Catalogue of Fossil 

 Sponges (1883); (2) British Fossil Sponges, Pal. Soc. 

 (1887-1912) ; (3) On Beds of Sponge-Remains in the 

 Greensands of the South of England, Phil. Trans. (1885). 



MINCHIN, E. A. Sponges, in Lankester's Treatise on 

 Zoology, Part II. 



ZITTEL, K. A. Studies on Fossil Sponges. Trans- 

 lated by W. A. Dallas, Ann. Nat. Mag. Hist. (1877-79). 



PROTOZOA. 



BRADY, H. B. Challenger Reports, vol. ix. (Zoology) : 

 Foraminifera (1884). 



CARPENTER, W. B., PARKER, W. K., AND JONES, T. R. 

 Introduction to the Study of the Foraminifera, Ray Soc. 

 (1862). 



CHAPMAN, F. The Foraminifera (1902). Contains a 

 good bibliography. 



