Regeneration . that pieces of the same orof different individuals could be united in various ways, and theunion become permanent. If the anterior end of one worm is united tothe posterior end of the same, or of another worm, a perfect union is B D Fig. 50. — A. Two pieces of Bipalium keivenseunited by anterior ends. B, C. Laterstages of same. Line in C indicates howpieces were cut apart. D. Two wormsproduced by these pieces. All drawn toscale. GRAFTING AND REGENERATION 171 formed, and no subsequent regeneration takes place (Fig. 52, A).Long worms can be made by uniting two pieces, each more th
Regeneration . that pieces of the same orof different individuals could be united in various ways, and theunion become permanent. If the anterior end of one worm is united tothe posterior end of the same, or of another worm, a perfect union is B D Fig. 50. — A. Two pieces of Bipalium keivenseunited by anterior ends. B, C. Laterstages of same. Line in C indicates howpieces were cut apart. D. Two wormsproduced by these pieces. All drawn toscale. GRAFTING AND REGENERATION 171 formed, and no subsequent regeneration takes place (Fig. 52, A).Long worms can be made by uniting two pieces, each more than halfthe length of a worm, or by uniting three pieces, as shown in Fig. 52, worms can be formed by cutting a middle piece from a worm,and uniting the anterior and posterior pieces (Fig. 53, D). Joestfound that when a short worm is made in this way, so that no repro-ductive region is present, the new worm does not produce new repro-ductive organs. It is conceivable that new reproductive organs might. Fig. 52. — After Joest. A. Union of two pieces oi Allolobophora terrestris in normal months after operation. B. Union of two pieces Lumbricus rubellus. Piecesturned i8o° with respect to each other. C. Union of three pieces oi A. terrestris to make along worm. D. Union of two worms (by anterior ends) from each of which eight an-terior segments had been removed. After three months. Regenerating two new A small piece oi Lumbricus rubellus grafted upon Allolobophora terrestris. Former re-generated end. have been produced either in the old segments, or by the formationof a new reproductive region between the two united pieces, butneither process takes place. In the long worms two sets of repro-ductive organs, etc., are present. This sort of union is, however,less permanent, as the worms often pull apart. Joest also united two posterior ends by their anterior many cases no regeneration took place, and, in the absence of a
Size: 1779px × 1404px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, bookpublisherlondo, bookyear1901
