150 DR. SCHULTZE, ON THE RHIZOPODA. 



5. Fam. Tubbinoida. — The spiral formed by the chambers resembles 



that of the shell of Helix or Turbo. The spiral 

 is only visible on one side of the shell. Some 

 are so much drawn out that the chambers are 

 disposed alternately, as it were, in two con- 

 tiguous rows. The shell has a large opening 

 in the last chainber, and the surface is almost 

 always finely perforate. 



1. Subfam. Botalida. — Shell depressed or conical ; chambers not 



embracing each other ; shell glassy, trans- 

 parent ; finely perforate. 

 Gen. Kotalia, Rosalina, Truncatulina, Anomalina, Planorbu- 

 lina, &c. 



2. Subfam. Uvellida. — Shell in the form of a longer or shorter raceme. 



The chambers frequently almost completely 



embracing. Shell usually thick and coarsely 



perforate, or solid. 



Gen, Globigerina, Bulimina, Uvigerina, Guttulina, Candeina, 



Globulina, Chrysalidina, Pyrulina, Clavulina, Poly- 



morphina, &c. 



3. Siibfam. Textilarida. — Spire so much produced that the chambers 



lie alternately in two contiguous rows. 

 Gen. Gaudryna, Textilaria, Virgulina, Vulvulina, Sagrina, 

 Bigenerina, &c. 



4. Subfam. Cassidullnida. — Textilaridans, curved once in a direction 



perpendicular to the original spiral. 

 Gen. Ehrenbergina, Cassidulina. 



6. Fam. Nautiloida. — The spiral formed by the chambers has a general 



resemblance to the shell of an Ammonite or 

 Nautilus. The spire is visible on each side of 

 the shell, or not visible on either side. The 

 anterior wall of the last chamber is furnished 

 with one larger or several smaller openings ; 

 the remainder of the shell is usually finely 

 perforate. 



1. Subfam. Cristellarida. — Shell thick, finely perforate, colourless, 



transparent ; chambers embracing, with 

 a large opening at the upper angle of 

 the anterior wa'l of the last chamber, 

 to which the communicating openings 

 between the separate chambers corre- 

 spond in position. 

 Gen. Cristellaria, Rotalina, Marginulina, Flabellina. 



2. Subfam. Nonionida. — Shell thick or thin, colourless, transparent, 



finely perforate ; chambers either em- 

 bracing or not. The opening in the 

 anterior wall of the first chamber at the 

 side looking towards the penultimate 

 S[nral ; the communicating openings of 

 the separate chambers in the correspond- 

 ing position. 

 Gen. Nonionina, Haverina, Orbignyna, Fusulina, Nummulina, 

 Assilina, Siderolina, Amphistegina, &c. 



3. Subfam. PenerojMda. — Usually thin, always brown, transparent 



sliells, with or without fine pores ; the 



