8 



NATURAL HISTORY. 



their relatives. Our plate shows the general appearance of one of the 

 forms, the delicate rays which extend to the margin being filaments of 



protoplasm, by means of which 



4 \\ 



locomotion is effected, and food 

 brought to the central mass 

 within the shell. In certain 

 localities, as at the Bermudas, 

 Charleston, S.C., Petersburg, Va., 

 etc., are large deposits of dead 

 or fossil foraminiferal shells, and 

 these places are the delight of 

 the microscopist. Every pinch 

 of the sand placed under the mi- 

 croscope shows their dead shells 

 in numbers, while the variety of 

 patterns is enormous. 



Another group of Protozoa is- 

 the Infusoria, so called from the 

 fact that some of its earliest 

 known members were first found 

 in infusions of hay, pepper, etc. 

 The Infusoria are regarded as- 

 being a step higher than the 

 Rhizopods which we have just 

 left, because there is more of a 

 differentiation of parts in them. 

 They do not have the power of 

 sending out protoplasmic lobes 

 or filaments, but they are usually enclosed in a protective envelope, and 

 bear either one or more long whiplash-like vibratile filaments (flagella), 

 or numbers of more rapidly vibrating hair-like bodies (cilia), the pres- 

 ence of one or the other of these serving to divide the group into 

 ciliated or flagellated Protozoa. 



Of the former group, Vorticella, the bell-animalcule, is known to every 

 tyro with the microscope, and well repays careful study. It consists of 

 a bell-shaped body, supported on a long, slender stalk, and is sure to 

 quickly attract attention from its peculiar motions. As one is looking 

 through the microscope, the body of the Vorticella suddenly disappears, 

 and on looking to see what has become of it, the observer soon finds it 

 drawn closely down to some solid object, its long, slender peduncle coiled 

 in a spiral. Gradually it straightens out, and as it does so it unrolls the 



Fig. 4. — A Protozoan ( Gromia) which lives 

 in moist earth. 



