These rotifers, belonging to the Notommatidae family, are characterized by their elongated, ovate, or spindle-shaped bodies with a slight constriction behind the mastax, separating the head and abdomen. They typically inhabit acid waters. Their foot is short and obscurely two-jointed, while their toes are notably long, often longer than the rest of the body, and usually unequal in length, although one species has equal toes. Their corona is slightly oblique and consists of a marginal wreath of cilia with lateral tufts of longer cilia adapted for propulsion. The mastax is an intermediate type between virgate and forcipate, with lyrate rami and inner margins armed with strong teeth below the mouth opening. The retrocerebral organ is underdeveloped, and the sac is ductless with rudimentary or absent glands. The eyespot is located at the posterior end of the ganglion. A notable feature of these rotifers is their mastax, which serves as an intermediate between the forcipate and virgate types. While resembling forcipate in a ventral view, its lateral view reveals curvature of the rami typical of the virgate mastax, along with large basal plates of the manubria. These structures support the walls of the mastax during the pumping action. However, the necessary changes to transform it into a forcipate mastax are minimal.