File:Biology (1917) (14585584379).jpg

Identifier: biology00calk (find matches)
Title: Biology
Year: 1917 (1910s)
Authors: Calkins, Gary N. (Gary Nathan), b. 1869
Subjects: Biology
Publisher: New York, H. Holt and company
Contributing Library: Internet Archive
Digitizing Sponsor: Internet Archive

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Fig. 56.—Cells from the en-doderm of a worm shomngenlarged gland cells with se-cretions, and between them,the absorptive cells. (FromK. C. Schneider.) VASCUT.AR SYSTEM OF THE EARTHWORM 143
Text Appearing After Image:
144 ORGANS AND ORGAN SYSTEMS reappear in the absorptive cells; chlorophyll and fat have alsobeen detected. The Rectum.—The rectum of the earthworm is the posteriorpart of the intestine, which bears no typhlosole. It opens to theoutside through the anus which is provided with a sphinctermuscle. According to Hensen, each worm deposits 1/2 gramof faeces in 24 hours, and these faeces make up the castingsshown by Darwin to have great economic importance. Further Fate of the Absorbed Nutriment.—The gut walls of theearthworm are richly supplied with blood vessels and finercapillaries which form a vascular network throughout the entireintestine. It is highly probable, although never demonstrated,that the absorbed food material is passed directly into the bloodthrough the walls of these vessels. E. Blood Vascular System.—In the earthworm it is theplasm or fluid that is colored red by haemoglobin, while theliving cells of the circulation are colorless. As in vertebrates,the blood flow is

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