526 Wisconsin Academy of Sciences, Arts, and Letters. 
ENTEROPLEA LACUSTEIS Ehrenberg. 
Plate XL, figures 1-5. 
Enteroplea lacustris Ehrenberg, Abh. Akad. Wiss. Berlin, 1830, p. 46; in 
Hemprich and Ehrenberg, Symb. Phys. Anim. Evert., Phytozoa, 1832 (?), 
pi. 3, fig. IV, 11.— Barring, Bull. 81 U. S. Nat. Mus., 1913, p. 44. 
Diglena lacustris Ehrenberg, in Hemprich and Ehrenberg, Symb. Phys. 
Anim. Evert., Phytozoa Polypi, 1832 (?), fob h (second page); Abh. 
Akad. Wiss. Berlin (for 1831), 1832, p. 136, pi. 3, fig. 10, pi. 4, fig. 14; 
(for 1833), 1834, p. 335, pi. 10, fig. 2; Infusionsthierchen, 1838, p. 442, 
pi. 54, fig. 4.— Dujardin, Hist. Nat. Zooph., 1841, p. 652.— Toth, Math. 
Termesz. Kozl., vol. 1, 1861, p. 187, (pi. 4) fig. 32. 
Triphylus lacustris Hudson, in Hudson and Gosse, Eotifera, Suppl., 1889, 
p. 19, pi. 32, fig. 16.— ^Western, Journ. Quekett Micr. Club, ser. 2, vol.'4, 
1890, p. 107, pi. 10, fig. 1; 1892, p. 374, pi. 25, fig. 5.— Bilfinger, Jahresh. 
Ver. Naturk. Wiirttemberg, vol. 48, 1892, p. 113.— Wierzejski, Eozpr. 
Akad. Umiej., Wydz. Mat.-Przyr., Krakow, ser. 2, vol. 6, 1893, p. 224. 
—Kertesz, Budapest Eotat. Faun.. 1894, p. 28.— Jennings, Bull. U. S. 
Fish Comm., vol. 19 (for 1899), 1900, p. 84— Voigt, Forschungsber. Biol. 
Stat. Plon, vol. 11, 1904, p. 40; Siisswasserfauna Deutschlands, pt. 14, 
1912, p. 110, figs. 207, 208.— Voronkov, Trudy Hidrobiol. Stants. Glu- 
bokom Oz., vol. 2, 1907, p. 95.— De Beauchamp, Arch. Zool. Exper., ser. 
4, vol. 10, 1909, pp. 24, 228, 341, figs. II A, XXXVI, LVII, pi. 9, figs. 
124—131.— Lucks, Eotatorienfauna Westpreussens, 1912, p. 47. fig. 6. 
—Weber and Montet, Cat. Invert. Suisse, pt. 11, 1918, p. 124, fig. 35. 
The body is short, saccate and very stout; its greatest width is 
nearly two thirds of the length of the body proper. The integu¬ 
ment is very soft and flexible, but the outline remains quite con¬ 
stant. The entire body is very hyaline. 
The head is short and very broad; it is separated from the ab¬ 
domen by a well defined constriction or neck immediately behind 
the mastax. The abdomen is slightly pyriform, ending posteriorly 
in a short, sleeve-like tail surrounding the base of the foot; postero- 
dorsally it has two parallel, deep, V-shaped grooves, caused by the 
pull of the dorsal retractor muscles, the broadened ends of which 
are attached to the internal apex of the V. The foot is indistinctly 
two-jointed, tapering and rather short, about one fifth of the length 
of the body; the terminal joint is nearly twice as long as the 
basal joint. The toes are nearly cylindric for one half of their 
length, with conical, acute points; their length is about one six¬ 
teenth of the total length. 
The dorsal antenna is a small, setigerous papilla in the normal 
position; the lateral antennae are quite close together, immediately 
in front of and above the tail. 
