Transactions of the Wisconsin Academy of Sciences, Arts and Letters
volume XXIII (1927)
Harring, H. K.; Myers, F. J.
The rotifer fauna of Wisconsin. IV. The Dicranophorinae, pp. -Plate 49 ff. PDF (41.5 MB)
Harring & Myers-Rotifer Fauna of Wisconsin.-IV. 689 Iy emptying ! slender, cy- I its contents bnder and so )osterior end Xarly as long posteriorly, The cervical -he openings toes 9-10,A; y placed at hio collected records this isbourg and g's Diglena ision of the ly justified. s may refer is not now bous poste- )f the total the outline Aotic zoo- tual width, ell marked Ms gradual- ;in young The tail foot is h, slightly onical and the total The dorsal antenna is a small, setigerous pit in the normal position; the lateral antennae are tubular, with a small tuf t of sensory setae. The corona extends down on the ventral side about one third of the length of the body; the post-oral portion pro- jects from the body as a rudimentary chin. The auricles are rather small and the ciliation continuous with the cor- ona. The mastax is virgate, but the pumping action is lost. The trophi are asymmetric and robust. The rami are ly- rate, broad and strongly divergent at the base, continuing as parallel, rather slender rods of irregularly triangular cross section, abruptly bent inward and knobbed at the tip, which is armed with five or six long, acutely pointed and slightly divergent teeth. The basal apophysis, which is nearly always present in the Notommatinae, is preserved as a broad rounded elevation on the ventral surface of the rami. On the dorsal side there is a remnant of the triangu- lar, lamellar extension of the rami in I. aurita, similar in form, but smaller; the oral combs are also present in this species. On the inner margin of the left ramus is a thin, narrow lamella nearly as long as the ramus itself, on the right a broad, finely striated, denticulate lamella, continu- ing from the base to the terminal, toothed knob. The alulae are large, pointed and decurved, with a lamellar extension continuing nearly to the tips, the right much broader than the left. The fulcrum is as long as the rami, broad at the base, reduced in the middle and expanded posteriorly. The unci are long, stout, slightly curved and acutely pointed; near mid-length is a knoblike enlargement resting on the rami and serving as a hinge; to it is attached a large secondary tooth, diverging slightly from the main tooth. The manubria are as long as the incus, nearly straight, broadly expanded anteriorly and abruptly curved posteriorly. The mastax is not protrusible through the mouth. Gastric glands are absent. The stomach has anteriorly two blind, fingerlike caeca, extending forward on the sides of the mastax almost to the ganglion; there is no distinct separation between stomach and intestine. A bladder is not present, the lateral canals emptying directly into the 44 r Letters. A I ,4q
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