FORAMINIFERA OF NORTH PACIFIC OCEAN. 27 



Length, up to 37.5 mm. 



Distribution. — In the Albatross material from the west coast of 

 Mexico and Central America this species forms what may be called 

 "Rhabdammina bottom," being the most common constituent of 

 the bottom in several places. In the material reported upon by 

 Goes, it occurred at Albatross station D3392, in 1,270 fathoms off 

 Panama, making up the mass of the dredged material. It also 

 occurred in 995 fathoms at station D3431, at the entrance to the 

 Gulf of California, in great quantity. These stations give all that 

 is known of its distribution in the North Pacific, as it has not been 

 noted in any of the other dredged material. At these stations 

 Rhabdammina abyssorum seems to be lacking. 



Throughout the mass of the material few specimens were found 

 which in any way suggested completeness of the test. Where there 

 is a long unbranched portion at the base it is usually somewhat curved. 

 That there may be more than the two branches is shown by the 

 figures given here. Just what the completed specimens are can not 

 be definitely stated with the material at hand, but a considerable 

 size is surely indicated. There seems to be a point of weakness just 

 above the region of forking, and the great majority of specimens are 

 broken at that point, as shown' in the figure. 



RHABDAMMINA DISCRETA H. B. Brady. 



Rhabdopleura, species, G. M. Dawson, Can. Nat., vol. 5, 1870, p. 177, fig. 7. 



Rhabdopleura abyssorum G. M. Dawson, Amer. Journ. Sei., vol. 1, 1871, p. 206 

 fig. 7; Ann. Mag. Nat. Hist., ser. 4, vol. 7, 1871, p. 86, fig. 7. 



Rhabdammina discreta H. B. Brady, Quart. Journ. Micr. Sci., vol. 21, 1881, p. 48; 

 Rep. Voy. Challenger, Zoology, vol. 9, 1884, p. 268, pi. 22, figs. 11-13.— Chap- 

 man, Proc. Zool. Soc. London, 1895, p. 14. — Goes, Bull. Mus. Comp. Zool., 

 vol. 29, 1896, p. 21, pi. 1, figs. 13, 14.— Flint, Rep. U. S. Nat. Mus., 1897, 

 (1899), p. 271, pi. 13.— EiMERand Fickert, Zeitschr. wiss. Zool., vol. 65, 1899, 

 p. 668.— Rhumbler, Arch. Protistk., vol. 3, 1903, p. 263, fig. 105 (in text).— 

 Bagg, Proc. U. S. Nat. Mus., vol. 34, 1908, p. 125. 



Description. — Test cylindrical, straight or nearly so, irregularly 

 constricted at intervals, with the effect of divisions exteriorly but no 

 corresponding walls within, open ends of the tube serving as apertures; 

 wall rather thin, firmly cemented of angular sand grains, roughish 

 on the exterior, but smoothly finished on the interior except at the 

 constrictions, where there. are various angles and irregularities; color 

 varying with the material used in the construction of the wall. 



Length indefinite, up to 25 mm. 



Distribution. — Rhabdammina discreta has been found at six widely 

 separated stations in the North Pacific. In the eastern portion it 

 occurs at Albatross station D3419, in 772 fathoms, off the coast of 

 Mexico in the material examined by Goes. Brady records its occur- 

 rence at one Challenger station in the western Pacific, west of the 



