FORAIMINIFEKA OF THE ATLANTIC OCEAN. 31 



which are somewhat constricted and rounded. Viewed as a transparent object (in 

 balsam) under a higli magnification, the wall of the tube is seen to contain large num- 

 bers of extremely minute rod-shaped l)odies, which are, as a rule, laid more or less at 

 riglil angles to the long axis of the tube, the characteristic metallic luster of the tube 

 when A-iewed as an opaque object is apparently due to the diffraction of the rays of 

 light falling on these parallel layers of spicules. The tube is not affected by l)oiling 

 in nitric acid for a few seconds, so the spicules can not lie calcareous. 



Length of tube, up to 2mm.; external diameter, 0.03 to 0.05 mm.; thickness of tube 

 wall, 0.002 to 0.004 mm.; spicules vary from 0.001 to 0.006 mm. in length. 



The authors described this species from Killary Bay, on the west 

 coast of Ireland. They record it also from 10 to 200 fathoms around 

 the coast of Scotland and in the North Sea across to the coast of 

 Norway. 



Although searched for, 1 have been unable to liiid this species in 

 material from this side of the Atlantic. 



Genus RHIZAMMINA H. B. Brady. 1879. 



Rkizninmimi H. B. Braky (type. R. olf/aeformis H. B. Bradj'), Quart. Jouru. 

 Micr. 8ci.. vol. 19, 1879, p. 39. — BtJTSCHLi in Bronn, Klasseu und Ordnungen 

 des Thierreichs, vol. 1, 1880, p. 195. — H. B. Brady, Rep. Voy. Challenger, 

 Zoology, vol. 9, 1884, p. 274.— Rhumbler, Arch. Prot., vol 3, 1903, p. 252.— 

 ('U3HMAN, Bull. 71, U. S. Nat. Mus., pt. 1, 1910, p. 33. 



Mdisipella (pnrti Eimer and Fickert, Zeitechr. Wiss. Zool., vol. (j5, 1899, p. (jG8. 



Description. — Test free, consisting of a simple or dichotomously 

 branching, flexible tube, wall largely chitinous, bearing various 

 foreign bodies attached to the exterior. 



Two species only are known and both occur in sniidl numbers as 

 far as the Albatross material has shown in the Atlautic but they are 

 widely distributed. 



RHIZAMMINA AL<JAEFORMIS H. B. Brariy. 



Plate J!, liKs. 2, 3. 



Rlnzanimina algaejormis H. B. Brady, Quart. Journ. Micr. feci., vol. 19, 1879, 

 p. 39, pi. 4, figs. 16, 17; Rep. Voy. Challenger, Zoology, vol. 9, 1884, p. 274, 

 pi. 28, figs. l-ll.~GoES, Bull. Mus. Comp. Zool., vol. 29, 1896, p. 20.— Flint, 

 Rep. U. S. Nat. Mus., 1897 (1899), p. 272, pi. 15, fig. 1.— Rhumbler, Arch. 

 Prot., vol. 3, 1903, p. 252, \ig. 92 (in text).— Cushman, Bull. 71, U. S. Nat. 

 Mus., pt. 1, 1910, p. 33, fig. 23 (in text). — Pearcey, Trans. Roy. Soc. Edin- 

 burgh, vol. 49, 1914, p. 999.— Herox-Allen and Earland, Trans. Zool. Soc, 

 London, vol. 20, 1915, p. (ill: Trans. Linn. Soc, London, vol. 11, pt. 13, 1916, 

 p. 221. 



Descnption. -^G^t free, consisting of a dicliotoniously 'branching 

 flexible tube, forming irregular masses of indefinite size; wall thin, 

 largely chitinous but with various sorts of foreign matter attached 

 to the exterior, cither sand or other foraminiferal tests according to 

 the character of the bottom outer surface when free from foreign 

 material somewhat r<nighened, color of the chitinous tubes brown 

 or gray. 



Diameter of tube, 0.] 26-0.3 15 mm. 



