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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Periacineta

Periacineta Collin, 1909 (ref. ID; 2013)

Class Kinetofragminophora: Subclass Suctoria: Order Suctorida: Suborder Evaginogenina (ref. ID; 2013)

[ref. ID; 2013]
Body usually inverted conical shape with a cup-like elongate lorica whose base is extended posteriorly to form a stalk-like region. The adult animal is flattened and the lorica may have transverse marking anteriorly denoting lines of growth (Nozawa, 1938). There is an apical slit-like aperture in the lorica through which the capitate tentacles protrude, usually from 2 fascicles. The macronucleus is rounded and reproduction is by endogenous buds. Most easily confused with Acineta which has a distinct stalk at the base of the lorica. It is regarded as a synonym of Discophrya according to Matthes (1954).
Quote; Colin R. Curds "British and other freshwater ciliated protozoa Part I Ciliophora: Kinetofragminophora" Cambridge University Press, 1982 (ref. ID; 2013)
  1. Periacineta buckei (Kent) (ref. ID; 1618)
  2. Periacineta gammari (ref. ID; 191)
  3. Periacineta linguifera Claparede & Lachmann (ref. ID; 3475)
  4. Periacineta tenuis Nozawa, 1938 (ref. ID; 3475 original paper)

Periacineta buckei (Kent) (ref. ID; 1618)

Descriptions

Attached end of lorica with basal plate; 3 contractile vacuoles; on Lymnaea stagnalis and Ranatra linearis. Matthes (1954) considers this a Discophrya. (ref. ID; 1618)

Measurements

Up to 125 um long. (ref. ID; 1618)

Periacineta tenuis Nozawa, 1938 (ref. ID; 3475 original paper)

Descriptions

The test is cup-shaped, but more elongated than in Periacineta buckei (Kent). The base of the cup is elongated in the form of a stalk and attached to the substratum. In adult individuals the test is compressed and provided with many distinct lines of growth on its surface. The body is fitted closely to the test. One contractile vacuole is present near the anterior end in the middle of the body. The macronucleus is ovoid, or more less sausage-shaped mostly ovoid in the young, and sausage-shaped in the adult individuals. The tentacle form two fascicles at the opposite angles of the anterior end; each fascicle comprises 5 to 20 tentacles, which are distinctly capitated and half as long as the length of the test. (ref. ID; 3475)

Comments

This new species is found in company with P. buckei, but may be distinguished from the latter in its general contour. Furthermore, the present species is about 1.5 times as large as, and more slender than P. buckei. The embryo of this new species is elongated and somewhat different from that of P. buckei. (ref. ID; 3475)

Type locality

On the shell of Viviparus from a pond in Husimi (Rokusizo), Kyoto (May, 1937), a pond in Matumoto, Nagano Pref. (August 1937), and from Lake Biwa (June 1937). (ref. ID; 3475)

Measurements

Length of test 100-190, breadth of anterior end 40-65 um. (ref. ID; 3475)