. Elementary text-book of zoology [electronic resource]. Zoology. ANNUL AT A. The blood-system is complex. The blood is respiratory in function and is said to contain haemoglobin, giving it a Blood Vas colour. The vessels lie between the coelomic cular epithelium and the alimentary canal or the body- wall, as the case may be. Along the whole length of the alimentary canal runs a median dorsal vessel in which the blood runs forwards. It supplies branches to the alimentary canal throughout its course, and it receives aerated blood from the last seven pairs of gills by paired efferent branchials.
. Elementary text-book of zoology [electronic resource]. Zoology. ANNUL AT A. The blood-system is complex. The blood is respiratory in function and is said to contain haemoglobin, giving it a Blood Vas colour. The vessels lie between the coelomic cular epithelium and the alimentary canal or the body- wall, as the case may be. Along the whole length of the alimentary canal runs a median dorsal vessel in which the blood runs forwards. It supplies branches to the alimentary canal throughout its course, and it receives aerated blood from the last seven pairs of gills by paired efferent branchials. Below the ali- mentary canal, but hanging free from it, runs the median ventral vessel. Its chief branches are thirteen pairs of affej-ent branchials taking blood to the gills and some to the nephridia. In this vessel the blood flows backwards, and it drains the regions of the alimentary canal supplied by the dorsal vessel. At the commencement of the stomach there are a pair of hearts. Each is two-chambered, consist- ing of an auricle and a ventricle. On contraction of the ventricles on each side the blood from the heart is driven into the ventral vessel. Over the stomach is a plexus of vessels, of which we may discern the two posterior lateral vessels and two sub-intes- tinals in the ventral wall of the stomach. The sub-intestinals receive blood from the first six pairs of gills by six efferent branchials on each side. The sub-intestinals communicate through small vessels with the posterior laterals, which carry the blood forwards and, together with paired asophageals on the oesophagus, fall on each side into the auricle of the heart, which on contraction drive the blood into the ventricles. We may summarise this rather complex arrangement by a diagram— AnTenor Posrarlor Dorsdl. Venfrdl. 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 perfect
Size: 3070px × 814px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, booksubjectzoology, bookyear1901
