spine-like processes, situated at equal distances around the entire periphery except at the anterior end.  Each spine is thick at the base and tapers to a full point which is curved upward—­i. e., dorsally (fig. 32, a, b).  The entire body is plastic and contractile, turning its leaf-like edge readily over objects upon which it creeps.  The cilia are fine and uniform, with a tendency to lengthen in the oral region.

Length 100 mu; greatest width assumed on contraction 85 mu; when normal about 50 mu.

[Illustration:  Fig. 32.—­Loxophyllum setigerum, var. armatum. a, b, c, ventral, dorsal, and lateral aspects.]

Genus LIONOTUS Wrzesniowski ’70.

(Incorrectly called Litonotus by many.  Entz ’84; Gruber ’84;
Buetschli ’88; Kent ’81; Schewiakoff ’89; Shevyakov ’96.)

The body is elongate and somewhat lance-shaped, widest at the central part and tapering to a point at the anterior end.  The posterior end may be similarly tapered or rounded.  The anterior end frequently proboscis-like, flat, and flexible, while the entire body is more or less elastic and contractile.  The right side is flattened and alone provided with cilia, while the left side of the body proper is arched; on the left side of the proboscis is a row of coarse cilia resembling an adoral zone, and a row of trichocysts.  A long peristome stretches down the thin, ventral side of the proboscis, and the mouth proper is situated at the junction of the proboscis and body; the mouth, as a rule, is invisible.  The ciliated right side alone is striated in the majority of species.  The contractile vacuole may be single or multiple, usually in the posterior region of the body and dorsal in position.  The macronucleus is usually double, rarely single or quadruple, but may occasionally break into numerous smaller pieces.  Movement, free-swimming or gliding, with especial tendency to get under clumps of foreign matter.

Fresh and salt water.

Lionotus fasciola Ehr.  Fig. 33.

Synonyms. Amphileptus fasciola Ehr. ’38; Dujardin ’41; Lachmann
          ’56; Cohn ’66, Diesing ’65.
          Loxophyllum fasciola Claparede & Lachmann ’58;
          Balbiani ’61.
          Loxophyllum duplostriatum Maupas ’83.  Shevyakov ’96.

Body frequently brown or brilliant yellow in color, somewhat sigmoid in form with tapering anterior end, the extremity of which is turned dorsally.  The proboscis is about half the entire length and is not sharply marked from the rest of the body but tapers gradually, its base being equal to the diameter of the body at its middle point.  The body is slightly contractile and the posterior end is carried to a rounded point, but not into a distinct tail.  Unlike the fresh-water variety, this one has no hyaline margin nor hyaline caudal region, and the contractile vacuole is double or multiple on the dorsal side near the posterior end.  Cilia are present only on the under