46 
THE VOYAGE OF H.M.S. CHALLENGER. 
Classification of the RHIZOPODA, R. Hertwig, 1879. 
Cellular organisms which move and nourish themselves by means of changeable extensions of their proto- 
plasmic bodies (pseudopodia). 
I. Monera. 
Rhizopoda without nucleus ; of indefinite changeable form. 
1. Gymnomonera-~M.orLe.xa. without skeleton. 
2. Lepomonera — Monera with skeleton. 
II. Amcebina. 
Rhizopoda with one nucleus or more than one; of indefinite changeable form; either without skeleton 
or with an irregular skeleton. 
1. Gymnamoebae — Amoebae without skeleton. 
2. Lepamoebce — Amoebae with skeleton. 
III. Thalamophora. 
Rhizopoda with one nucleus or more than one, and a chitinous monaxial shell which is usually cal- 
careous externally, and always possesses one or two openings for the passage of the pseudopodia. 
1. Monothalamia — Shell single-chambered, not calcareous. 
(a) Amphistomata, shell open at both ends. 
(b) Monostomata, shell open at one (oral) extremity, closed at the opposite end. 
2. Polytlialamia — Shell calcareous, with an opening at the oral extremity ; generally consisting 
of many chambers, which are arranged one after the other in a straight or a (spiral or 
irregular) curved row. 
(a) Imperforata, shell-wall solid. 
(b) Perforata seu Foraminifera, shell-wall perforated with numerous small pore-canals. 
IV. Heliozoa. 
Rhizopoda of globular form, with one nucleus or more ; with radiating pseudopodia, pointed and thread- 
like, issuing from every part of the surface. 
1. Aplirothoraca seu Adinophryidce — Heliozoa without skeleton. 
2. Chalarothoraca seu Acanthocystidce — Heliozoa with a skeleton which is formed of distinct 
pieces. 
3. Desmothoraca seu Clathrulinidai — Heliozoa with a clathrate or net-like ball. 
V. Radiolaria. 
Rhizopoda of rounded shape, with one nucleus or more, which united with a part of the sarcode. and 
enclosed by a membrane, forms the central capsule; with a gelatinous envelope, and with radiating, 
pointed, thread-like pseudopodia issuing from the surface. 
1. Thalassicollidce. 
2. SpJicerozoidce. 
3. Tripylidce. 
4. Peripylidce. 
5. Monopylidas. 
6. Acanthometridce. 
Note . — The following additional or alternative arrangements are proposed by Professor 
Hertwig for sections III. and IV. -V. 
