328 PAL/EONTOLOGY 



cyclina limestones (commonly known as orbitoidal) have 

 a similar distribution and are found in the West Indies 

 also. Although the accumulation of these giant Forami- 

 nifera to a sufficient extent to form masses of lime- 

 stone is confined to the site of this great tropical and 

 sub-tropical ocean, the genera are occasionally found 

 beyond its limits. Thus Nummulites spread as far as 

 Hampshire in the latter part of the Eocene period, and 

 Lepidocyclina into Bavaria in the Oligocene. 



This completes the survey of the Animal Kingdom 

 as known in the fossil state, but for a few minor groups 

 that have been omitted and may briefly be mentioned 

 here. 



The Bryozoa (or Polyzoa) are a phylum or sub- 

 phylum of fixed compound animals, having some super- 

 ficial likeness to the corals, but belong to a decidedly 

 higher grade. They are often united with the brachiopods 

 under the name Molluscoidea. Their skeleton (zoarium) is 

 made up of many more or less tubular individual 

 skeletons (zocecia), which are much smaller in size than 

 most corallites, and have no septa. In a few simple 

 cases the zoarium is like a branching thread ; very often 

 it forms a flat lamina, either spreading freely in the 

 water or encrusting other organisms ; sometimes it is 

 massive, in which case it may become difficult to draw 

 the line between this phylum and the Alcyonaria, 

 especially as structures analogous to tabulae may be 

 present. Certain Palaeozoic forms have been referred to 

 the one phylum by some investigators, and to the other 

 by others. The Bryozoa are almost exclusively marine, 

 and range from the Ordovician to the Recent period. 

 Occasionally they occur in such abundance as to form 



