66 FORAMINIFERA 



state most of the records are from recent material. 

 Rhabdammina and Astrorhiza which are the most firmly 

 cemented have been recorded as far back as the Jurassic, and 

 it will probably be found that their history is much older than 

 this, owing to the difficulty of recognizing fossils of this char- 

 acter in the older rocks. 



FAMILY 3. RHIZAMMINIDAE 



Test consisting of a tubular chamber open at both ends; wall 

 with a chitinous lining and exterior of agglutinated foreign 

 material, arenaceous grains, sponge spicules or other foramin- 

 if era ; apertures formed by the open ends of the tubes. 



KEY TO THE GENERA 



I. Test cylindrical, not branching. 



A. Wall of sand grains and sponge spicules. 



1. Exterior showing the spicules Marsipella. 



2. Exterior smooth, spicules mostly on the interior; wall 



thick Bathysiphon. 



B. Wall mostly of f oraminiferal tests, test short Brachysiphon. 



II. Test usually branching, wall of foraminiferal tests and chitin, 



Rhizammina. 



Genus MARSIPELLA Norman, 1878 



Plate 3, figures 1-3 

 Genoholotype, Marsipella elongata Norman 



Marsipella Norman, Ann. Mag. Nat. Hist., ser. 5, vol. 1, 1878, p. 281. 

 Proteonina W. B. Carpenter, Proc. Roy. Soc. London, vol. 18, 1869, p. 

 60 (not Proteoniva Williamson, 1858). 



Test free, tubular, cylindrical or fusiform, sometimes re- 

 curved at the ends; wall thin, firmly cemented, composed wholly 

 or in part of sponge spicules, or the middle part of sand grains ; 

 aperture formed by the open ends of the tube or sometimes 

 closed at one end by a loosely aggregated knob of spicules. 



Jurassic to Recent. 



The species are mostly found in cold water, but one species 

 at least is abundant in rather warm water in less than a 

 hundred fathoms off the coast of Florida. None of the many 

 specimens of this warm water form show the peculiar head of 



