. Elements of zoölogy : a textbook. Zoology. WORMS CONSIDERED AS A CLASS. 371. nc Transverse section oi a Worm. *, skin or body wall; nc, double nervous cord or nervous ganglions ; ac, aliment- ary canal ; ft, heart or dorsal vessel ; to, locomotive organs or tubercles tipped with bristles or hairs; nc', supplementary nervous cord; ft', supplementary circulatory vessel. bristles (Fig. 505), or plates which serve as locomotive organs. Those provided with bristles or setse, are called Chaetopods, from the Gr. chaite, hair, and pousy a foot. Their digestive system is very simple. Their circula- t
. Elements of zoölogy : a textbook. Zoology. WORMS CONSIDERED AS A CLASS. 371. nc Transverse section oi a Worm. *, skin or body wall; nc, double nervous cord or nervous ganglions ; ac, aliment- ary canal ; ft, heart or dorsal vessel ; to, locomotive organs or tubercles tipped with bristles or hairs; nc', supplementary nervous cord; ft', supplementary circulatory vessel. bristles (Fig. 505), or plates which serve as locomotive organs. Those provided with bristles or setse, are called Chaetopods, from the Gr. chaite, hair, and pousy a foot. Their digestive system is very simple. Their circula- tory system is but little more than a dorsal vessel or so- called heart. Their blood in many cases is red. They respire by means of branchiae, or by the whole surface of the body. Their nervous system, even when present, is nearly equally distributed among the different segments. The Annelida have the sense of touch highly developed, and many are provided with tactile organs. As to sight, in many (Serpula, jLumbricus, etc.) eyes are wholly want- ing; in others there are two or more very distinct eyes. Organs of hearing have been detected in some ; and it is believed that many can perceive sounds. Worms multiply by means of eggs ; and some kinds also increase by gemmation or fission—that is by self-division (Fig. 506). A few are viviparous. In most kinds the sexes are distinct; but in some kinds (Earthworms, Leeches, etc.) the two sexes are united in the same individual. Worms live in the water, in mud, in damp earth, and. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Tenney, Sanborn, 1827-1877. New York : Scribner
Size: 1872px × 1334px
Photo credit: © Paul Fearn / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthortenn, bookpublishernewyorkscribner, booksubjectzoology
