CLASSIFICATION OF THE ANIMAL KINGDOM. 



Fam. b. Polycystina. Podocyrtis, Dictyocha, Lychno- 



canium. 



Fam. c. Collozoa. Collozoum, Sphcerozoum. 

 Fam. d. Thalassicollida. Thalassicolla, Thalassolampe. 



Sub-ord. 2. Heliozoa. Actinosphcerium, Heterophrys. 



It is still a matter of opinion whether the Heliozoa should be regarded 

 as a division of the Radiolaria, or as a distinct order of Rhizopods. The 

 chief differences which separate the Heliozoa from the typical Radiolar- 

 ians are, that the former possess no central membranous capsule and no 

 gelatinous investment, both these structures being, as a rule, present in 

 the latter ; but in other respects there is a close general likeness between 

 the two. 



(Hseckel, Die Radiolarien, 1862 ; Schneider, Zur Kenntniss der Radio- 

 larien, Zeitschr. f. Wiss. Zool., 1871 ; Greeff, Ueber Radiolarien, &c., des 

 sussen Wassers, Archiv fur Mikr. Anat., 1869 ; Mivart, Recent Researches 

 on the Radiolaria, Journ. Linn. Soc., 1878 ; Archer, Resume of Recent 

 Contributions to our Knowledge of Freshwater Rhizopods, Quart. Journ. 

 Micro. Sci., 1876, 1877; Huxley, On Thalassicolla, Ann. Nat. Hist., 

 1851). 



CLASS in. INFUSORIA. 



ORDER I. FLAGELLATA. Monas, Cercomonas, Monosiga (fig. 

 6, E), Codosiga, Euglena, Peridinium, Cemtium (fig. 6, D). 



ORDER II. SUCTORIA (Tentaculifera, Sav. Kent). Podo- 

 phrya, Acineta. 



ORDER III. CILIATA. 



Sub-ord. 1. Holotricha. Paramcecium, Enchelys, Colpoda, 



Amphileptus (fig. 6, c). 

 Sub-ord. 2. Heterotricha. Bursaria (fig. 6, A), Stentor, 



Codonella, Nyctothems (fig. 6, B). 



Sub-ord. 3. Peritricha. Trichoderia, Vorticella, Epistylis. 

 Sub-ord. 4. Hypotricha. Aspidisca, Euplotes, Chilodon. 



There is much ground for separating the so-called Suctorial and Flag- 

 ellate Infusoria as two distinct and independent classes of the Protozoa. 

 The latter, in particular, have very close affinities with the Sponges, 

 though they are essentially unicellular organisms. 



