Earring (& Myers—Rotifer Fauna of Wisconsin — II. 441 
The corona is an elongate oval area covering the oblique ante¬ 
rior surface of the head and continuing beyond the mouth on the 
ventral surface as a projecting chin; the marginal cilia are rela¬ 
tively short, except on two latero-frontal areas, provided with long 
and powerful cilia adapted to swimming, in the majority of species 
seated on auricles, short tubular, retractile evaginations of the in¬ 
tegument. The apical plate is nearly always enclosed by the mar¬ 
ginal ciliation and has frequently a projecting skinfold or rostrum, 
at the base of which are the openings of the ducts of the retro- 
cerebral organ; the buccal field and chin are covered with very 
short, dense cilia; the mouth is approximately in the center. 
The mastax is virgate and usually somewhat asymmetric; the 
fulcrum is very large and nearly at a right angle to the roughly^ 
hemispherical rami, which are occasionally faintly denticulate on 
the inner edges; the manubria are long and expanded anteriorly 
into broad plates; the unci have at least one strongly developed 
ventral tooth and usually some additional, more or less rudimen¬ 
tary teeth. The piston is a powerful, muscular organ, filling the 
entire cavity of the mastax and attached to the fulcrum. Two 
rod-shaped transverse supports are imbedded in the walls of the 
mastax below the posterior margin of the rami; some very small, 
accessory teeth are frequently attached to the ventral margin of 
the unci; an epipharynx is rarely present. 
The retrocerebral organ is highly developed; the sac is always 
present and the subcerebral glands are found in all but a very 
few species. The eyespot is at the posterior end of the ganglion. 
Type of the genus.—Notommata aurita (Muller) = Vorticella 
aurita Muller. 
A large number of species have been described which we have 
not been able to identify satisfactorily with any of the species 
known to us. The majority are probably now to be considered as 
hopeless; in some cases, at least, it is clear that the same name has 
been used for a number of actually quite different species. Notom¬ 
mata brachyota is apparently a valid species, if we may judge 
from the number of records, but we have not found an animal that 
could be made to agree with Ehrenberg’s description. 
Notommata hrachyota Ehrenberg, Abh. Akad. Wiss. Berlin (for 1831), 1832, 
pp. 51, 132, pi. 4, fig. 8; Infusionsthierchen, 1838, p. 435, pi. 51, fig. 3.— 
Hudson and Gosse, Rotifera, 1886, vol. 2, p. 24, pi. 17, fig. 1 .—Wierzejski, 
Rozpr. Akad. Umiej., Wydz. Mat.-Przyr., Krakow, ser. 2, vol. 6, 1893, p. 228. 
