THE PROTOZOA OF THE SEA SHORE 



105 



we scrape up a little of the surface sand, following the exact course 

 of one of these whitish streaks, and examine the material obtained 

 by the aid of a good lens, we shall in all probability discover a 

 number of minute shells among the grains of sand. 



These shells are of various shapes little spheres, discs, rods, 

 spirals, &c. ; but all resemble each other in that they are perforated 

 with a number of minute holes QIC foramina. They are the skeletons 



FIG. 54. A GROUP OF FORAMINIFERS, MAGNIFIED 



of protozoons, belonging to the class Rhizopoda, and they exist in 

 enormous quantities on the beds of certain seas. 



We will first examine the shells, and then study the nature of 

 the little animals that inhabit them. 



The shells vary very much in general appearance as well as in 

 shape. Some are of an opaque, dead white, the surface somewhat 

 resembling that of a piece of unglazed porcelain ; others more 

 nearly resemble glazed porcelain, while some present quite a vitreous 

 appearance, much after the nature of opal. In all cases, however, 

 the material is the same, all the shells consisting of carbonate of 



