FAMILY 3. RHIZAMMINIDAE 67 



loosely aggregated sponge spicules as found in the North Sea 

 specimens and recorded by Heron-Allen and Earland. 



Genus BATHYSIPHON M. Sars, 1872 



Plate 3, figures 4-6 

 Genoholotype, Bathy siphon filiformis M. Sars 

 Buthysiphon M. Sars, in G. O. Sars, Forh. Vidensk.-Selsk. Christiania, 

 1871 (1872), p. 251. 



Test free, cylindrical, often tapering slightly, straight or more 

 often somewhat curved, in some species externally constricted 

 but not internally divided ; wall composed of a base of broken 

 sponge spicules cemented and overlaid with a fine grained 

 amorphous material, either soft or firmly cemented, often with 

 a very thin surface coating ; apertures at the ends of the tube. 



Cretaceous to Recent. 



The species are most abundant in cool water at rather shallow 

 depths in high latitudes and at corresponding temperatures and 

 greater depths in the tropics. 



Genus RHIZAMMINA H. B. Brady, 1879 



Plate 3, figures 7-10 



Genoholotype, Rhizammina algaeformis H. B. Brady 



Rhizammina H. B. Brady, Quart. Journ. Mlcr. Sci., vol. 19, 1879, p. 39. 



Marsipella (part) Eimer and Fickert, Zeitschr. Wiss. Zool., vol. 65, 



1899, p. 668. 



Test a simple or dichotomously branching tube ; wall flexible, 

 chitinous, with various foreign bodies, usually other foramin- 

 iferal tests attached to the exterior; apertures formed by the 

 open ends of the tubes. 



Cretaceous to Recent. 



There is a possibility that the species of this genus have been 

 broken in dredging, and that when perfect they may be attached 

 and not open at the base. 



Genus BRACHYSIPHON Chapman, 1906 



Plate 3, figures 11, 12 

 Genoholotype, Brachysiphon corbuliformis Chapman 

 Brachysiphon Chapman, Trans. New Zealand Instit., vol. 38, 1905 

 (1906), p. 83. 



Test free, a roughly cylindrical short tube ; wall with an inner 



