GENUS ACTINOPHKYS— ACTINOPHKYS SOL. 235 



ACTINOPHRYS SOL. 



Plate XL. 



" Un poisson dcs plus extraordinaire que Von en puisse voir." Joblot : Obs. Hist. Nat. i, 1754, 64, pi. 7, 

 fig. 15. 



Trichoda Sol. Mtillcr: Verm. Terrest. Fluv. 1773,76. Anim. Infus. 1786,164, tab. xxiii, figs. 13-15.— 

 Schrank : Fauna Boica, iii, 2, 1803, 93. 



Peritricha Sol. Bory: Encycl. M6th., Vers. 1824. 



Aclinoplirys Sol. Ebrenberg : Abh. Ak. Wis. Berlin, 1830, 42, 53, 61, 76, Taf. ii, Fig. 4 ; 1831, 102. Infusions- 

 thierchen, 1838, 303, Taf. xxxi, Fig. vi.— Dujardin : Infusoires, 1841, 262, pi. iii, fig. 3.— 

 Perty: Kennt. kleinst. Lebensfonnen, 1852, 169.— Stein : Infusiontbicre, 1854, 151 — Clapa- 

 rede and Laebmann : Etudes Infusoires, i, 1858-59, 450.— Pritchard : Hist. iDfus. 1861,559, 

 pi. xxiii, figs. 28, 31, 32.— WaUich: An. Mag. Nat. Hist. 1863, xi, 446, pi. x.fig. 4— Cien- 

 kowski: Arch. mik. Anat. i, 1865, 227.— Grenacher: Verb, pkys.-med. Gesells. Wiirzb. i, 

 1868, 170, Taf. iii.— Hertwig and Lesser: Arcb. mik. Anat. x, 1874, 164, Taf. v, Fig. 2.— Mi- 

 crographic Dictionary, pi. 23, fig. 7 6.— Leidy : Pr. Ac. Nat. Sc. 1874, 23. 



Actinophrys difformis. Ebrenberg: Abh. Ak. Wis. Berlin, 1831, 102. Infusionstbierchen, 1838, 304, Taf. 

 xxxi, Fig. 8. 



Aciinophrys Eichhornii. Claparede : Midler's Archiv, 1854, 398, Taf. xv, Fig. 1-6. 



f Aciinophrys oculata. Stein : Die Infusionsthiere, 1854, 151, 157, Taf. v, Fig. 25. Organismus Infusions- 

 thiere, ii, 1867, note to p. 5, "A. oculata nur eine marine Form von A. sol."— Pritchard: 

 Hist. Infus. 1861, 560, pi. xxiii, figs. 24, 25. 



Animal spherical, translucent, vesicular or foamy, the vesicles usually- 

 numerous, more or less crowded and usually uniform. Contractile vesicle 

 single, large, active. Nucleus commonly obscured from view. Rays numer- 

 ous, straight, from one to three or four times the length of the diameter of 

 the body. 



Size. — Diameter of body from 0.04 mm. to 0.12 mm., with pseudopods 

 commonly from 0.08 mm. to 0.16 mm. in length. 



Locality. — In all quiet waters with aquatic plants. Observed in many 

 parts of the United States, Nova Scotia, and Canada. 



Actinophrys sol, the common Sun-animalcule, is one of the most 

 familiar and striking forms of microscopic life of still fresh waters. When 

 first seen, it would hardly be suspected to pertain to the animal kingdom, 

 though Joblot, its earliest observer, spoke of it as "a fish the most extraor- 

 dinary that one may see." Plate XL. 



It may be found in almost every standing water-pool, pond, or lake, 

 swimming among aquatic plants; its favorite haunts being duck-meat, 

 hornwort, bladderwort, or the various filamentous alga?. It commonly 

 appears as a globular, hyaline, foamy or vesicular body, bristling with 

 delicate rays, and suspended almost stationary in the water. 



