2 BULLETIN 104, UNITED STATES NATIONAL MUSEUM. 



Description. — Test composed of a series of cliambers in a coil, each 

 chamber making a half coil of 180° and embracing so that but a 

 small part of the preceding chamber is visible from the exterior; 

 wall smooth, finely perforate, either thin and transparent or thick 

 and opaque; aperture at the inner margin of the ventral face of the 

 chamber curved, often with a slightly upward-turned lip. 



This genus has been described as composed of an alternating series 

 of chambers, but in reality it seems to be a coiled test in v/hich each 

 chamber takes up 180° of the volution. The peculiar form of the 

 test is distinctive, as is the form of the aperture. ChiJostomeUa 

 ovoidea Reuss is thin walled and very widely distributed; C. grandis 

 Cushman is known as yet only from the Pacific about the Philip" 

 pines. The species described from the London Clay as Lagena 

 {OUiquina oviformis) Sherbbrn and Chapman ^ seems to be a species 

 of Chilostomella and should be known as Chilostomella oviformis 

 (Sherborn and Chapman). The geological range of the genus there- 

 fore is from the Eocene to the present oceans. 



From the very wide distribution of C. ovoidea and its thin test it 

 might be supposed to be pelagic, but little is known of it except as 

 a bottom-living species. 



CHILOSTOMELLA OVOIDEA Reuss. 



Plate 1, figs. 1-10. 



Chilostomella ovoidea Reuss, Denkschr. Akad. Wiss. Wien, vol. 1, 1850, 

 p. 380, pi. 48, fig. 12.— H. B. Bradt, Quart. Journ. Micr. Sci., vol. 

 19, 1879, p. 280, pi. 8, figs. 11, 12; Rep. Voy. Challenger, Zoology, 

 vol. 9, 1884, p. 4.36, pi. 55, figs. 12-23; Journ. Roy. Micr. Soc, 1887, 

 p. 901. — Sherborn and Chapman, Journ. Roy. Micr. Soc, 1889, p. 

 485, pi. 11, fig. 12. — Pearcey, Trans. Glasgow Nat. Hist. Soc, vol. 2, 

 1890, p. 177.— Wright, Proc. Roy. Irish Acad., ser. 3, vol. 1, 1891, 

 p. 476. — Egger, Abh. kon. bay. Akad. Wiss. Mlinchen, CI. II, vol. 

 18, 1893, p. 305, pi. 9, figs. 1, 2.— Goes, Kongl. Svensk. Vet. Akad. 

 Handl., vol. 25, 1894, p. 53, pi. 9, figs. 512-516; Bull. Mus. Comp. 

 ZooL, vol. 29, 1896, p. 50. — Chapman, Journ. Linn. Soc. Zool., vol. 

 28, 1901, p. 402.— Millett, Journ. Roy. Micr. Soc, 1901, p. 2, pi. 

 1, figs. 2, 3. — GoDDARD, Rec. Austr. Mus., vol. 6, 1905-7, p. 307.— 

 SiDEBOTTOM, Mem. Proc. Manchester Lit. Philos. Soc, vol. 54, No. 

 16, 1910, p. 14.— Cushman, Bull. 71, U. S. Nat. Mus., pt. 4, 1914, 

 p. 2, pi. 1, figs. 1-5. — Mestayer, Trans. New Zealand Inst., vol. 48, 

 1916, p. 129.— SiDEBOTTOM, Joum. Roy. Micr. Soc, 1918, p. 129.— 

 Cushman, Proc U. S. Nat. Mus., vol. 56, 1919, p. 621; Bull. 100, 

 U. S. Nat. Mus., vol. 4, 1921, p. 283. 



Description. — Test composed of several chambers in a coil, each 

 chamber 180° from the preceding, the chambers all visible from the 

 dorsal side, but the two last-formed ones making up nearly the whole 

 surface of the test; chambers increasing very rapidly in size as 



1 Journ. Roy Micr. Soc, 18S6, p. 745, pi. 14, figs. 19 a-d. 



