XVIII. Description of an infusory animalcule allied to the genus Notommata of Ehrenberg, hitherto undescribed

Abstract

The animalcule I propose to describe in the present memoir bears so close a resemblance to Notommata Syrinx of Ehrenberg, that were there not special differences in its internal anatomy, such as I believe could not have been overlooked by that great observer, one might almost believe it to be the same animal. The character of the genus is thus given by the Professor in the great folio of 1838:—“Animal ex Hydatinæorum familia, ocello unico occipitali, pede bisulco, caudam furcatam referente ; et organo rotatorio, simpliciter ciliato, instructum.” These characteristics are mostly taken from its external organs; but we find, on reference to the description of the animal, that it possesses an intestinal tube terminating in a cloaca or anal orifice, which appears from the plates to be situated at the point where the foot or forcipated tail emerges. The grand structural difference, then, to be remarked in the animalcule that forms the subject of the following pages, is that there exists no intestine, and therefore no anal orifice, nor any tail or forcipated extremity. This want of intestine removes it into a lower position, as regards animal life, and I would therefore refer it to a subgenus of Notommata, if it be even entitled to a place so high in the scale of Infusoria.