ANIMALCULE ALLIED TO NOTOMMATA. 
337 
Every animal, however low in the scale of beings, is nourished by some process of 
converting either animal or vegetable products into themselves ; but when we observe 
such elaborate organs of alimentation in Notommata, such as those of prehension, 
mastication, deglutition and digestion, we may infer at least the existence of some 
apparatus that may suflSce to circulate and aerate the elaborated fluid or blood. A 
process of respiration is equally important to these beings as food and digestion, for 
it is well known that the higher forms of infusory animals will not exist in water 
either deprived of air or in which the air has been consumed by long inhabitation. 
The contractions of the vesicle I have described resemble very closely the expirations 
of a vesicular lung, and in some forms of Rotifera it appears almost wholly to vanish 
when contracted, and by expansion again to become suddenly apparent. 
With regard to the nervous system, traces of such an apparatus may be distinctly 
recognised in the optic lobe or mass of ganglionic matter, on the centre of which is 
placed the pink pigmentous matter constituting the organ of vision (Plate XXXIII. 
fig. 1 C) ; from this nervous mass a fine filament may be observed passing obliquely 
down the body of the animal, attached at about the centre of the outer tegumentary 
case, Plate XXXIII. fig. 1 T. At this point exist two small tubercles, around which are 
set three or four short hairs, cilia, or setse. The filament connecting these tubercles 
with the optic lobe, is enlarged at its lower part by the addition of two or three 
small ganglionic globules (Plate XXXIII. fig. 7 E), and appears to send off* delicate 
filaments to the stomach, salivary glands, ovaries and ovisac. It may be a question 
also v/hether the curved and looped fibres connected with the circulatory organ may 
not have ganglionic corpuscles intermingled with them. 
The muscular system is best explained by reference to the drawing, Plate XXXIII. 
fig. 8. It is merely necessary to remark here, that besides the long ribbon-shaped 
muscles that serve to contract and to retract the head and body, there are numerous 
muscular filaments having their fixed points in the integumentary case, and inserted 
into the various internal organs upon which they act ; thus, there are delicate muscles 
attached to the fundus of the stomach to retract it into its situation after it has been 
drawn up to the pharynx either to receive or reject its food. 
Other muscles are fixed to the ovaries ; and a very intricate set of reticular fibres 
are expanded over both the respiratory sac and ovisac, producing in the one case the 
strong expiratory contractions of this vesicle, and in the other the expulsatory action 
attending the birth of the embryo. 
The broad ribbon-shaped muscles have faint indications of cross markings, as seen 
in the voluntary muscles of higher animals, and in young specimens have frequently 
still remaining the nuclei of the cells imbedded in the fibre, whence this tissue has 
been originally developed. 
The other more conspicuous organs visible within the transparent body of this 
animalcule are those appropriated to the reproduction of the species, and are very 
perfect in their kind. 
