82 MANUAL OF ZOOLOGY. 



are much less mobile than in the case of the Amoeba. The 

 division of the substance of the body into ectosarc and endo- 

 sarc is tolerably evident, and the latter contains numerous 

 granules and vacuoles. The pseudopodia are derived from 

 the ectosarc alone, the endosarc not passing into them, and 

 they exhibit a circulation of granules along their edges, though 

 this is not nearly so marked a feature as in the case of the 

 Foraminifera. A nucleus and contractile vesicle are also 

 present. 



Actinophrys occurs in both fresh and salt water. Actino- 

 sphczrium is in many respects like Actinophrys ; but each of the 

 pseudopodia is supported upon a strong albuminous spine ; 

 and the sarcode of the body is vesicular or " alveolar," while 

 numerous nuclei exist in the central sarcode. In Heterophrys 

 (fig. 22), there is a globular body, the ectosarc of which is sur- 

 rounded by a kind of external investment or excretion, which 

 appears to be of a protoplasmic nature, but takes no part in the 



Fig. 22. Heterophrys spinifera, one of the Heliozoa, greatly enlarged. (After Hertwig 

 and Lesser.) c c Contractile vesicles. 



production of the pseudopodia. The latter are long, granular, 

 and unbranched, and amongst them are long spine-like pro- 



