14 THE ROTIFERA. 
shows the chief longitudinal muscles. The ovary (fig. 2a) is very large, and has large 
germs: a maturing ovum is visible in fig. 2. A large nervous ganglion of Notommatan 
type stretches back from the corona to the dorsal surface and bears a large red eye. I 
failed to find any antenne. The male is unknown. 
Length, 7; inch. Habitat. Near Birmingham (T.B.): rare. 

Family X. NOTOMMATADA. 
(Corona obliquely transverse ; ciliary wreath of interrupted curves and clusters, 
usually with a marginal wreath surrounding the buccal orifice ; trophi forcipate ; foot 
furcate. 
The Rotifera associated in this family may be considered the most typical repre- 
sentatives of the whole class. They are permanently free, never affixed to other objects, 
never to each other in clusters. Their bodies are not inclosed in tubes; their integu- 
ment is more or less flexible, never hardened into a shelly mail. The body is generally 
cylindrical, with a length twice or thrice the diameter : the front does not expand into a 
flower-like disk, but is usually convex, often with a flat versatile face, inclined down- 
wards (supposing the animal to be crawling), beset with strong vibrating cilia, so arranged 
that their combined action produces two vortices, one on each side of the head. The 
posterior extremity bears a foot of several diminishing joints, capable, in a slight degree, 
of telescopic inversion ; and the last of these bears two diverging toes, chitinous in 
structure, used for support and locomotion. 
The trophi are well developed, all the seven constituent elements—the labrwm, the 
two mallei, the two icus-rani, the fulerwm and the labiwn—corresponding homo- 
logically to the labrum, the mandibles, the mawille and the labiwm, of insects,! being 
present, in relative proportions. The mastax is so placed that the jaws can be freely 
protruded from the buccal orifice, as has been seen in most of the genera, and used, 
forceps-like, to slit the cells of Alge, to nibble the flocculent matter which grows on 
vegetable stems, or to seize, retain, and devour active animalcules. 
Some of the genera possess a singular apparatus for suddenly augmenting locomotion, 
in the form of a pair of organs (auricles), ordinarily concealed, which can be thrust out 
in an instant, by eversion of the skin. The surface which is then external is clothed 
with cilia, dense, vigorous, and capable of producing ample vortices in the water. 
The Notommatade@ are the most highly organised of all Rotifera; the most sudden, 
varied, and energetic in their motions; most highly endowed with external sense- 
organs; most predatory ; most nearly approaching to the Articulate classes, not only in 
their manducatory organs, but also in their skin usually firm, elastic, capable of being 
thrown into transverse folds, or sub-articulations, more or less permanent. If not the 
most beautiful, they may claim to be the most interesting; best repaying investigation, 
while they present the greatest difficulties to the student. As this must be considered 
the central or typical family, without adopting all the fancies of the Circular theories, 
we may suggest that the relation between the genus Furcularia and the Loricata, 
through Diaschiza, is very close: that Proales, with its long prone face, leads to the 
Bdelloida through Adineta: that the skipping species of Fwrcularia, as longiseta and 
equalis, look towards the Scirtopoda: and that in the mucous investiture common in 
the genus Copeus, we perceive a reflection of the excreted tubes of the Rhizota.— 
P.H.G.] 
' See my mem. “ On Mand. Organs,” Phil. Trans. 1855 p. 449. 
