138 



PROTOZOA. 



pillars or imperfect partitions (fig. 35). We might readily 

 be disposed to regard these singular forms as aberrant and 

 gigantic Foraminifera, but in no case has it been satisfac- 

 torily proved that the calcareous walls of the fossil are 



Fig. 35. a, Fragment of Stromatopora granulata (Devonian), of the natural size, showing 

 the upper surface, with stellate water-canals ; &, Vertical transparent section of the same, 

 magnified ; c, Horizontal transparent section of the same enlarged still further ; d, Vertical 

 section of another Stromatoporoid (Clathrodictyon cellulosum), enlarged. In figs, b and c the 

 skeleton is dark, and the light spaces represent transparent calcite ; but in fig. d the latter 

 represent an infilling of silica. (Original.) 



penetrated by microscopic tubuli. The spaces between the 

 successive laminae are, however, placed in communication by 

 means of a more or less largely developed series of pores, 

 and we can hardly avoid the conclusion that the entire fossil 

 in its living condition was permeated by continuous sar- 

 code ; so that we must regard it as referable to the sub- 

 kingdom of the Protozoa. The mass of the fossil is also 

 often penetrated by larger or smaller canals, which can 

 hardly have served any other purpose than that of con- 

 veying water to different parts of the organism (fig. 36, a), and 

 which may fairly be compared with the " aquiferous canals " 

 of the Sponges. The surface of the mass, also, often exhibits 

 conical elevations, or papillae, which are perforated at their 

 summits by the apertures of water-canals, and from which 

 there radiate branched and vermiculate grooves, these char- 

 acters strongly reminding us of some of the living Sponges 

 (see fig. 35). It should be added that many palaeontologists 



