6 BULLETIN 104, UNITED STATES NATIONAL MUSEUM. 



Description.^Test elongate, tapering, composed of two series of 

 alternating chambers; wall calcareous in the young, hyaline and 

 perforate, occasionally so throughout the test, often with an external 

 coating of siliceous or calcareous sand, or in some species nearly the 

 whole test arenaceous; aperture typically an arched slit at the inner 

 margin of the chamber close to its line of attachment to the preceding 

 chamber; occasionally with the aperture surrounded by a raised lip, 

 or in some species with the aperture circular and terminal. 



There are numerous modifications in the species of the genus due 

 mainly to differences in the amount and the direction of compression. 

 Except for spines and accessory growths of the sutures and periphery 

 there is little ornamentation. The young of the microspheric form 

 is often coiled but usually not that of the megalospheric form. Typi- 

 cally the genus consists of forms with an arenaceous test, either 

 smoothly finished or rough, with a series of chambers alternating on 

 opposite sides of a central axis. The aperture typically is in a reen- 

 trant of the inner margin of the apertural end but in some species 

 may become terminal or even a series of pores. 



From this genus are developed numerous forms such as Bigenerina, 

 etc., which have evidently been derived from such forms as Textularia. 

 Its geological history goes very far back, at least into the Paleozoic. 

 Its range is given by Chapman as Cambrian to Recent, In the 

 present oceans it reaches its best development in shallow water of 

 tropical seas but is abundant in some parts of the temperate zone, 

 and a few species live at considerable depths. 



TEXTULARIA SAGITTULA Defrance? 



Specimens from two stations, D2311, in 79 fathoms (145 meters), 

 and D2314, in 159 fathoms (291 meters), off the southeastern coast of 

 the United States, may possibly belong to this species although they 

 are not typical. They are represented by single specimens and a 

 note of their occurrence is all that can be done with them at the 

 present time. 



Much more typical specimens of this species occur off the coasts 

 of Europe, as is noted by many authors. 



Textularia sagittula — material examined. 



