24 



PHYSIOLOGY OF THE INVERTEBRATA. 



different functions do not follow the same lines in the animal 

 series. Nor will the advance of particular functions keep 

 pace with the advance in anatomical structure. As far as- 



Fig. 2. — Various Protozo.\. 



A = Gregarina. B = Amceba. C = Magosphrera. D = Actinophrys. 

 E = Actinosphferium. F = Part of E highly magnified. 

 V = contractile vacuole, w = nucleus. 



structure is concerned, the Gregarina ranks higher than the 

 Amcebn. 



(h) The Amoeba. — In the Profoplasta, to which the Amoeba 

 belongs, we have a distinct advance in the mechanism of 



