80 



BULLETIN 10 4, UNITED STATES NATIONAL MUSEUM 



Test complanate, planispiral, early portion with the coils of nearly 

 uniform diameter, but in later coils rapidly increasing in height, form- 

 ing a broad, flattened test; spiral suture distinct; wall smooth except 

 for the thickenings caused by the lines of growth; aperture, a long 

 narrow slit the entire height of the chamber. 



Length of largest specimens 10 millimeters or more. 



This species develops to its maximum in the colder waters of the 

 Arctic and North Temperate Zones. It is widely distributed in the 

 Tarious ocean basins but reaches smaller proportions elsewhere. 



Cornus-pira foliacea — Material examined 



CORNUSPIRA INVOLVENS (Reuss) 



Plate 20, Figures 6, 8 



Operculina involvens Reuss, Denkschr. Akad. Wiss. Wien, vol. 1, 1850, 

 p. 370, pi. 46, fig. 30. 



■Cornuspira involvens Reuss, Sitz. Akad. Wiss. Wien, vol. 48, Abt. 1, 1863, p. 

 39, pi. 1, fig. 2; vol. 50, abt. 1, 1864, p. 450; Denkschr. Akad. Wiss. Wien, 

 vol. 25, 1865, p. 121. — Jones, Parker, and H. B. Brady, Pal. Soc. Mon. 

 19, 1866, p. 3, pi. 3 figs. 52-54.— Karrer, Sitz. Akad. Wiss. Wien, vol. 58, 

 abt. 1, 1868, p. 131. — Hantken, Magy. kir. foldt. int. evkonyve, vol. 4, 

 1875 (1876), p. 16, pi. 2, fig. 2.— H. B. Brady, Ann. Mag. Nat. Hist., ser. 

 5, vol. 8, 1881, p. 401; Denkschr. Akad. Wiss. Wein, vol. 43, 1881, p. 8; 

 Proc. Roy. Soc. Edinburgh, 1882, p. 714; Rep. Voy. Challenger, Zoology, 

 vol. 9, 1884, p. 200, pi. 11, figs. 1-3. — Andreae, Abhandl. Geol. Special- 

 Karte Elsass-Loth., vol. 2, pt. 3, 1884, p. 127. — Balkwill and Millett, 

 Journ. Micr., vol. 3, 1884, p. 5, pi. 1, fig. 1. — Balkwill and J. Wright, 

 Trans. Roy. Irish Acad., vol. 28, Sci., 1885, p. 327, pi. 12, figs. 2 a, 6.— 

 Burbach, Zeitschr. Nat., vol. 59, 1886, p. 497, pi. 5, fig. 1. — Siddall, Proc. 

 Lit. Phil. Soc. Liverpool, 1886, p. 63 (list). — H. B. Brady, Parker, and 

 Jones, Trans. Zool. Soc, vol. 12, 1888, p. 216, pi. 40, figs. 1-3.— Sherborn 

 and Chapman, Journ. Roy. Micr. Soc, 1889, p. 484, pi. 11, figs. 4, 5. — 

 Halkyard, Trans. Manchester Micr. Soc, 1889, p. 62. — Howchin, Trans. 

 Proc Roy. Soc. So. Australia, vol. 12, 1889, p. 4; vol. 13, 1890, p. 164.— 

 Chaster, First Rep't. Southport Soc. Nat. Sci., 1890-91 (1892), p. 56.— 

 J. Wright, Proc. Roy. Irish Acad., ser. 3, vol. 1, 1891, p. 466. — Chapman, 

 Journ. Roy. Micr. Soc, 1891, p. 575, pi. 9, figs. 12 a, b. — Egger, Abhandl. 

 kon. bay. Akad. Wiss. Mimchen, CI. II, vol. 18, 1893, p. 246, pi 3, figs. 

 18, 19.— Woodward, The Observer, vol. 4, 1893, p. 77.— Hosius, Nat. Ver. 

 Osnabruck, Jahrb. 1893-94 (1895), p. 77.— Jones, Pal. Soc. Mon. 19, pt. 

 2, 1895, p. 128, pi. 3, figs. 52-54, figs. 11 a, b in text.— Flint, Ann. Rep't. 

 U. S. Nat. Mus., 1897 (1899), p. 303, pi. 48, fig. 3.— Morton, Proc. Port- 

 land Soc. Nat. Hist., vol. 2, 1897, p. 114. — Millett, Journ. Roy. Micr. 

 Soc, 1898, p. 612.— J. Wright, Irish Nat., vol. 9, 1900, p. 53.— Chapman, 



