Outlines of comparative physiology touching the structure and development of the races of animals, living and extinct : for the use of schools and colleges . anization;the mouth is large, opening into an esophagus and stomach,in which are found gastric teeth, a distinct intestine, and anus ;around the head are numerous ball-shaped bodies, furnishedwith cilia, which perform motions resembling those of a revolv-ing wheel. The group is therefore called ROTIFERA (fig. 172).The structure of the digestive organs of many of the inferiorforms of polygastrica is still involved in much obscurity ; but i
Outlines of comparative physiology touching the structure and development of the races of animals, living and extinct : for the use of schools and colleges . anization;the mouth is large, opening into an esophagus and stomach,in which are found gastric teeth, a distinct intestine, and anus ;around the head are numerous ball-shaped bodies, furnishedwith cilia, which perform motions resembling those of a revolv-ing wheel. The group is therefore called ROTIFERA (fig. 172).The structure of the digestive organs of many of the inferiorforms of polygastrica is still involved in much obscurity ; but inthe higher forms, as in Leucophrys patula(fig. 171), these organs become visible whenthe animalcule has been fed with minuteparticles of carmine diffused through thewater. The body is covered with long cilia,which form a circle round the mouth,their vibrations causing currents of waterto flow therein, together with the minuteparticles on which Leucophrys subsists ;the intestine is seen taking a windingcourse through the body, having appendedto its walls numerous globular cells, many -pis. 171.—Leucophryiof which are distended with colouring 162 OllGAKS OF DIGESTION. matter, and forming a natural injection of the gastric cavi-ties ; the anus opens at *, from which egesta are often seenexuding. [§ 314. The Eosphora najas is typical of the rotifera. The body (fig. 172) is enclosed in a doubleelastic tunic, into which the muscles areinserted ; its anterior part is truncated,and furnished with globular bodies armedwith vibratile cilia; this rotatory apparatusis moved by muscles inserted into the base of the ciliiferous organs; the eyes areseen at #, a, b; the pharynx (c) is largeand capacious, and the stomach (d) isprovided with a triturating apparatus,which in many allied genera is armed withjawrs. The intestine terminates in the anusat d; the ovary, with many ova, is seen at/.The posterior extremity of the body is fur-nished with a pair of forceps, by whichthe rotifer
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectzoology, bookyear1870
