188 



PROTOZOA. 



differentiations of the sarcode, particularly of the central capsule. 

 One or more nuclei may be present in the central mass. An im- 

 portant distinguishing mark is afforded by the presence of the 

 pulsating vacuoles, which have not been observed in any marine 

 Hadiolarian. 



The reproduction very frequently takes place by fission, occasionally 



FIG. 129. Thalassicolla pelagica, with central capsule and single largenucleus, also numerous 

 alveoli in the protoplasm (after E. Haeckel). 



after previous conjugation of one or more individuals, also during 

 encystment. Multiplication by spores has also been observed 

 (Clathrulina). 



in the Actinopliryidfs there is no skeleton secreted : ActinosphcEriv/m 

 Eidilnn'n'tl Ehrbg. The central matter contains numerous nuclei. ActinopJirys 

 sol Ehrbg. of small size, with a single central nucleus. 



In the A<'antlicnxti(l(e slender silicious spikes are found : Ai-tintJtoci/xtix 

 Sjthtifera Greet!, with silicious spikes and needles. 



In Clatfii'iilhta there is a latticed silicious shell, and the body has a stalk : 

 Chitliniliini eleg&ns Cienk. 



