98 FORAMINIFERA 



is found in deep water. In the largest megalospheric forms of 

 Hormosina, a single chambered form is developed hardly sep- 

 arable from some species of Saccammina except by the fine 

 material of the test and the apertural characters. 



FAMILY 7. AMMODISCIDAE 



Test composed of a globular proloculum and long undivided 

 tubular second chamber, usually close coiled, at least in the 

 young, planispiral, conical spiral or irregularly winding; wall of 

 fine arenaceous material with much cement, usually of a 

 yellowish- or reddish-brown color ; aperture formed by the open 

 end of the tubular chamber. 



KEY TO THE GENERA 



I. Test free. 



A. Test completely coiled throughout. 



1. Planispiral at least in the young. 



a. Planispiral throughout AniTnodiscus. 



b. Planispiral in the young, later coils partially covering one 



side Hemidiscus. 



2. Conical spiral at least in the young. 



a. Conical spiral throughout Turritellella. 



b. Conical spiral in the young, later nearly planispiral. 



Arnmodiscoides. 



3. Irregularly winding Glomospira. 



B. Test partially uncoiled. 



1. Tubular chamber not compressed Lihiotuba. 



2. Tubular chamber compressed, complanate Psammonyx. 



II. Test attached. 



A. Early portion coiled. 



1. Later portion irregularly winding Tohjpammina. 



2. Later portion bending back and forth Ammovcrtella. 



B. Early portion a single chamber, remainder nearly straight. 



Ammolagena. 



