FOEAMINIFERA OF NOETH PACIFIC OCEAN. 



49 



Genus THOLOSINA Rhumbler, 189S. 



Placopsilina H. B. Brady (part), Quart. Journ. Micr. Sci., vol. 19, 1879, p. 51; 



vol. 21, 1881, p. 51; Rep. Voy. Challenger, Zoology, vol. 9, 1884, p. 314. 

 Tholosina Rhumbler, Nachr. kon. Ges. Wiss. Gottingen, 1895, p. 82; Arch. 



Protistk., vol. 3, 1903, p. 226. 

 Pseudoplacopsuina Eimer and Fickert, Zeitschr. wiss. Zool., vol. 65, 1899, 



p. 672. 



Description. — Test attached, hemispherical, flattened on the side 

 by which it is attached, chamber single, undivided; walls fairly thick, 

 composed of sand grains with a large proportion of calcareous cement, 

 walls roughened on the exterior. 



The single species of this genus has been found but rarely in the 

 North Pacific. It is easily distinguished when it is attached to dark 

 colored tests like Rhabdammina, as its white color shows up strikingly 

 against the darker background. 



Rhumbler seems to be quite right in making a new genus for this 

 species, which is quite different from the genus to which it has usually 

 been assigned. The name proposed by Eimer and Fickert will have 

 to go into the synonymy and the earlier name proposed by Rhumbler 

 will stand. 



THOLOSINA BULLA (H. B. Brady). 



Placopsilina bulla H. B. Brady, Quart. Journ. Micr. Sci., vol. 21, 1881, p. 51; 

 Rep. Voy. Challenger, Zoology, vol. 9, 1884, p. 315, pi. 35, figs. 16, 17.— GoEs, 

 Kongl. Svensk. Vet. Akad. Handl., vol. 25, no. 9, 1894, p. 28, pi. 6, figs. 213- 

 215 (not figs. 211, 212= Ammolagena); Bull. Mus. Comp. Zool., vol. 29, 1896, 

 p. 25.— Millett, Journ. Roy. Micr. Soc, 1899, p. 361, pi. 5, fig. 11. 

 Tholosina bulla Rhumbler, 

 Nachr. kon. Ges. Wiss. 

 Gottingen, 1895, p. 82.— 

 Kler, Norske Nordhavs- 

 Exp., No. 25, 1899, p. 

 4. — Rhumbler, Arch. 

 Protistk., vol. 3, 1903, p. 

 227, fig. 52 (in text). 

 Pseudo placopsilina bulla 

 Eimer and Fickert, Zeit- 

 schr. wiss. Zool., vol. 65, 

 1899, p. 672. 

 Description. — Test adher- 

 ent hemispherical or strongly 

 convex, flattened at the base 

 to conform to the surface to 

 which it is attached, usually 

 slightly longer in one di- 

 rection than the other; 

 chamber single, usually un- 

 divided, walls thick, composed of sand grains with an excess of cal- 

 careous cement, surface uneven, apertures simple, nearly circular, 

 16777— Bull. 71—10 4 



Fig. 55.— Tholosina bulla, x 15. 

 FROM side. 



a, from above; b, 



