MORPHOLOGY 



41 



beautiful shells with various ornamentations or incorporation of 

 foreign materials. Many pelagic radiolarians possess numerous con- 

 spicuous radiating spines in connection with the skeleton, which ap- 

 parently aid the organisms in maintaining their existence in the open 

 sea. 



Fig. 4. Diagram of the shell of Fetieroplis pertusus, X about 35 

 (Carpenter), ep, external pore; s, septum; sc, stolon canal. 



Certain Protomonadina possess a funnel-like collar in the flagel- 

 lated end and in some in addition a chitinous lorica surrounds the 

 body. The lorica found in the Ciliophora is mostly composed of 

 chitinous substance alone, especially in Peritricha, although others 

 produce a house made up of gelatinous secretion containing foreign 

 materials as in Stentor (p. 645). In the Tintinnidae, the loricae 

 are either solely chitinous in numerous marine forms not mentioned 

 in the present work or composed of sand-grains or coccoliths ce- 

 mented together by chitinous secretion, which are found in fresh- 

 water forms. 



Locomotor organellae 



Closely associated with the body surface are the organellae of 

 locomotion : pseudopodia, flagella, and cilia. These organellae are not 

 confined to Protozoa alone and occur in various cells of Metazoa. 

 All protoplasmic masses are capable of movement which may result 

 in change of their forms. 



Pseudopodia. A pseudopodium is a temporary projection of part 

 of the cytoplasm of those protozoans which do not possess a definite 

 pellicle. Pseudopodia are therefore a characteristic organella of 



