38 



BULLETIN 104, UNITED STATES NATIONAL MUSEUM. 



figured groups it is a linear series of three distinct chambers unconnected except by 

 the elongate "tent-pole" spicules. 



We have experienced some hesitation in allotting this interesting species to its 

 genus. In spite of the selective power displayed, the test is e\'idently of the simplest 

 type of Rhizopod structure, and the absence of a definite oral aperture combined with 

 the evidence which we have discovered of selective power in another unquestion- 

 able species of Psammosphaera (P. bowma7iii, sp. n.). has guided us in our decision 

 to refer the specimen to the genus PsainmaspJinent. 



P. rustica, though never of very frequent occurrence, is met with at several of the 

 Goldseeher stations round the coast of Scotland. It occurs most frequently at Sta- 

 tions IX and IXB in the North Sea (61° M' N. ; 2° 4' E., 390 meters), and stations 53 

 (59° 36^ N.; 70° W.. 1,000 meters) and haul 228 (57° 59' N.; 10° 34' W., 1,600 meters). 

 on the west coast of Scotland, but occasional specimens are to be met with at inter- 

 medin to localities and depths. 



PSA\5N!OSFHAERA TESTACEA (Flint). 



Plate 15, figs. 1-3. 

 Psammosphaera Jmcu, var. testacea Flint, Ann. Rep. U. S. Nat. Mus., 1897 (1899), 



p. 268, pi. 8, fig. 2. — Heron-Allen and Earland, Journ. Roy. Micr. Soc, 



1913, p. 18, pi. 2. fig. 9. 

 Psammosphaera fusca Heron-Allen and Earland. .Tourn. Quekett Micr. Club, 



ser. 2, vol. 10. 1909, pi. 33. fig. 4. 



Descnption. — Test free, siibspherical, wall composed of the empty 

 tests of other foraminifera, cemented firmly, the interior of the 

 single chamber smooth, exterior very rough; no definite aperture, 

 the fine interstitial openings apparently serving for apertures. 



Diameter, up to 3 mm. 



Dutribntion. — Flint described this form from the Gulf of Mexico, 

 Albatross stations D2358, 2383, and 2399, in 196 to 1,181 fathoms. 

 Heron-Allen and Earland record it from about Great Britain. It 

 has occurred frequently in Globigerina ooze. In their paper Heron- 

 Allen and Earland record the species at but 7 out of 145 stations 

 from which material was examined, and at only 2 of these was it 

 recorded as common. These were in 362 and 1,600 meters, the 

 latter off St. Kilda, west of the Hebrides, in Glohigerina-ooze. They 

 give the following note. In comparing this with P. parva, "F. 

 fusca, var. testacea is of an entirely different habit. It can not in 

 any way be regarded as a selective organism, but rather as a Psam- 

 mosphaera which utilizes the tests of other Foraminifera in the 

 construction of its 'house' merely because they chance to be the 

 material most ready to hand." 



Psammosphaera lestaeen — material examined. 



