SPECIAL MORPHOLOGY AND TAXONOMY OF SARCODINA 349 



Family 6. Castanellidse, Haeckel. —Shells usually globular or mon- 

 axonic with uniformly distributed wide, rounded pores, and usually 

 with numerous radial spines distributed on all sides. 



Family 7. Circoporidse, Haeckel.— Shells globular or polyedral, with 

 a crown of pores at the base of the radial spines. The latter which 

 are limited in number and have terminal branches, are usually 

 arranged in geometrical ])atterns. 



Family 8. Tuscaroridse, Haeckel. —Shells usually flask-form with 

 narrow pore canals and rather short unbranched radial spines 

 grouped in one or two crowns about the main axis. 



Family 9. Porospathidse, Borgert.— Shells with papilliform excres- 

 cences or covered with a trigonal meshwork. Radial spines present 

 on all sides. 



Sub-order 4. Phaeogromia, Haeckel. 



Here the skeleton is usually bilaterally symmetrical with a shell 

 mouth and definitely localized radial spines. 



Family 10. Challengeridae, J. ^Murray.— Shells with "diatom" 

 structure; shell opening with a one-sided "peristome" formation. 

 Radial spines if present only in the median plane more rarely grouped 

 around the aboral ])ole. 



Family 11. Medusettidae, Haeckel. — Shells smooth or ornamented 

 with small spines. Radial spines limited exclusively to the edge 

 of the shell mouth 



Sub-order 5. Phseoconchiae, Haeckel e^l Haecker. 



Here the shells consist of two usually thick-walled valves which 

 are perforated by rounded or slit-like pores. 

 Family 12. Concharidse, Haeckel. 



Sub-order G. Phaeodendria, Haecker. 



Shells consisting of two thin-walled valves each with a conical 

 process from which originate diverging, branched tubes. 

 Family 13. Ccelodendridse, Haeckel, em. Haecker. 



KEY TO COMMON GENERA OF SARCODINA. 



Class H. RHIZOPODA, von Sieb. 



1. Naked; Heliozoa-hke; radiating pseudo- 



podia Sub-class 1. Proteomyxa 



Naked or shelled; pseudoijodia not Helio- 

 zoa-like 2 



2. With myxopodia and Plasmodium forma- 



tion Sub-class 2. Mycetozoa 



No Plasmodium formation 3 



3. With calcareous shells; marine Sub-class 3. Foeaminifera 

 Naked or with chitinous tests Sub-class 4. Amceb.ea 



