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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Octotrocha

Octotrocha Thorpe

ref. ID; 1663

Corona with eight prominent lobes and one small median dorsal lobe. In a gelatinous tube. (ref. ID; 1663)
  1. Octotrocha speciosa Thorpe, 1893 (ref. ID; 1345, 1663, 1923, 2810, 3508)

Octotrocha speciosa Thorpe, 1893 (ref. ID; 1345, 1663, 1923, 2810, 3508)

Descriptions

This species was described from China, and has been reported from a number of localities in the United States. However, there is some doubt about the specific and even the generic identity of the American form with Thorpe's. His description states that there is a wide dorsal gap, but the American form has a small, distinct, dorsal lobe in place of the gap. Thrope's figure gives the distinct impression of being made from a partly contracted specimen, and it is possible that the small dorsal lobe was missed. In anterior view, the lobe is not seen. The American form would be more properly described as having 3 pairs of lobes than 4, but specimens have been observed to stand with the large ventral lobes partly folded in such a way as to give the appearance of 2, as in Thorpe's drawing. The trophi of the American form, while clearly malleoramate, are unique in the reduction of the small teeth and the enlargement of the large ones. Thorpe's figure of trophi also show 3 large teeth. It differs in detail, but he evidently drew a crushed preparation, and small details cannot be trusted. The animal is sessile; either solitary, or crowded together in large groups when common. May be confused with Lacinularia if the corona is not observed. (ref. ID; 1923)