6o 



THE INVERTEBRATA 



Order RHIZOMASTIGINA 



Zoomastigina with one or two flagella, and the whole surface of the 

 body permanently amoeboid. 



Mastigamoeba (Fig. 47 A). One flagellum; numerous, finger-like 

 pseudopodia. In fresh waters. 



^Mm 



-(mo)— I 



V.Cc.l. 



V42. 



Fig. 45. Diagrams to show the structure of the colony of two species of 

 Volvox. After Janet. V.a.i. Surface view of a small part of the colony of 

 V. aureus. V.a.z. Section through a similar region. V.g.i. and V.g.2. show 

 V. globator in the same way. The zooids are very different in shape in the two 

 species, but in both they have been separated by the formation of mucilage 

 {mu) by the cell-walls; the unaltered middle layer of the walls {m.l.) is still 

 visible. Protoplasmic strands (p.c), fine in the one species and thick in the 

 other, connect the zooids. Each zooid, with its curved chloroplast (ch) often 

 containing more than one pyrenoid, its eye-spot, and two flagella, has the 

 structure of a Haematococcus. 



Order HOLOMASTIGINA 



Zoomastigina with numerous flagella, and the whole surface of the 

 body capable of amoeboid action. 



Multicilia. Spherical, with 40 or 50 flagella scattered evenly over 

 the whole surface, at any point on which food can be ingested by 

 amoeboid action. A marine species with one nucleus; freshwater 

 species multinucleate. 



