Lectures on the comparative anatomy and physiology of the invertebrate animals : delivered at the Royal College of Surgeons . the higher anellids. In the leech the vascular system consists principally of four greattrunkSj none of which present any local dilatations meriting thename of heart; one of these trunks is situated on each side, a thirdabove, and a fourth below, the alimentary canal. They are shownin transverse section, as connected together in two of the middlesegments of the leech in the diagram {Jig. 105.), from Brandts The lateral trunks (c, c) are the largest; they ar
Lectures on the comparative anatomy and physiology of the invertebrate animals : delivered at the Royal College of Surgeons . the higher anellids. In the leech the vascular system consists principally of four greattrunkSj none of which present any local dilatations meriting thename of heart; one of these trunks is situated on each side, a thirdabove, and a fourth below, the alimentary canal. They are shownin transverse section, as connected together in two of the middlesegments of the leech in the diagram {Jig. 105.), from Brandts The lateral trunks (c, c) are the largest; they are widestin the posterior third of the body; their anterior end terminates inbranches to the head; the posterior end unites with that of its fellow * CXC. p. 173. t CLXXXV. ANNUL AT A. 235 more conspicuously than at the anterior part, and supplies the ter-minal sucker. Branchesare given off at eachring, which almost im-mediately divide into adorsal {d) and ventral(e) ramulus; the six pos-terior dorsal branchesunite with those of theopposite side, and thesix arches thus formedare joined together bynear the middle line of. Leech. two nearly parallel longitudinal vesselsthe back. The dorsal vessel {Jig. 105. a), in which the blood moves from behindforwards, is formed by the union of the dorso-intestinal vein and ofthe dorso-dermal vessel, which run parallel with each other alongthe posterior third of the body. The trunk is thence continuedforwards, sending outwards a pair of transverse branches at eachring, and bifurcating behind the mouth to enclose the the under part of the oesophageal ring the great ventral vein{Jig. 105. b) begins, which is continued along the nervous ganglionicchord, and swells at each ganglion, forming a sinus around it; thenervous matter being thus, as it were, bathed in the nutrient fluid.*From each of these swellings a transverse branch is sent off to eitherside {f,f\ and from the seventh to the fifteenth ganglionic sinus asecond pair of tr
Size: 2049px × 1219px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorowenrichard18041892, bookcentury1800, bookdecade1850
