Genus ANOPLOPHRYA Stein '60.

(Stein '60; Claparède '60; Leidy '77; Vejdovsky '79;
Kent '81; Balbiani '85; Bütschli '88; Shevyakov '96.)

The general form is elongate, cylindrical or slightly flattened, with rounded ends, the posterior end tapering. The body is striated with clearly defined, often depressed lines, which run longitudinally and sometimes spirally. The contractile vacuoles are usually placed in rows upon the edges. The macronucleus is almost always long and band-formed, rarely oval, and generally extending through the entire length of the body. Micronuclei have been made out in one case. Reproduction is effected by simple cross division or by budding at the posterior end, and is frequently combined with chain formation. The main characteristic is the entire absence of mouth and œsophagus, the animals being parasitic in the digestive tract of various annelids. Parasites, salt-water forms.

Anoplophrya branchiarum. Stein '52. Fig. 44.

A. circulans Balbiani.

The body is cylindrical to pyriform, in the latter case broadened anteriorly. Cuticle distinctly marked by longitudinal striations which take the form of depressions and give to the body a characteristic melon shape. The endoplasm contains a number of large refringent granules—probably body products. The nucleus is elongate, somewhat curved, and coarsely granular. A micronucleus lies in the concavity. The cilia are long, inserted rather widely apart along the longitudinal markings. The contractile vacuole is single and is located at the pointed end, which is directed backwards during locomotion. One specimen found free swimming among some algæ.

Length 104µ; greatest diameter 36µ.


Fig. 44.—Anoplophrya branchiarum.
[ ENLARGE ]

I was much surprised to find this form swimming about freely in the water; its mouthless condition showed it to belong to the family of parasites, the [Opalinidæ]. As the name indicates, however, this species is an ectoparasite upon the gills, and Stein gave the name branchiarum to a fresh-water form parasitic upon Gammarus pulex. The Woods Hole form is so strikingly similar to the figure of G. branchiarum that, although the name was given to a fresh-water form, it obviously applies to this marine variety. One important difference is the presence of only one contractile vacuole in the marine form.