File:The pedigree of man - and other essays (1903) (14578277757).jpg

Identifier: pedigreeofmanoth00haec (find matches)
Title: The pedigree of man : and other essays
Year: 1903 (1900s)
Authors: Haeckel, Ernst Heinrich Philipp August, 1834-1919
Subjects: Man Evolution Man Evolution
Publisher: London : A and H.B. Bonner
Contributing Library: ASC - York University Libraries
Digitizing Sponsor: York University - University of Toronto Libraries

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ae cones (Strobilae), developed by distal gemmationfrom two hydra polyps (Fig. 5 c.) Each Strobila consists ofeight young Medusae, placed in a row, one after the other,like links in a chain, a the older, b the younger Strobila. Amongst the lower or craspedote Medusae, on theother hand, to which the Carmarina belongs, the polyps,or first generation that are developed from the Medusaeeggs, give rise, by gemmation, to a tree-like, branchingor creeping colony. From this colony, again, Medusaespring, detaching themselves later on ; or special buds(metamorphosed polyps), in each of which manyMedusae originate by gemmation (Fig. 7 /.) Such a colony may, therefore, bear two different or-ganisms, wholly unlike externally, that have sprung bydivision of labor from the same original hydraformpolyp. The one set of polyps, the long-stalked foodpolyps (Fig. 7 a, b) are concerned only with eating,drinking, digestion, but can form no more eggs. Theypossess an open mouth and a circle of tentacles, but
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Fi 7. A creeping polyp colony (Campanularia Johnstoni). On thecreeping root stock (e) are placed two hydra polyps that areas result of division of labor wholly diverse in their develop-ment. The long-stalked are food polyps (a~d), the short- THE DIVISION OF LABOR. 107 stalked are reproductive (/.) The latter form buds that de-velop into Medusae, and swim away (g.) The former areable to withdraw (b) their outstretched bodies within ahorny envelope (c.) Their stalk (d) is annulate at top andbottom. they have lost the power of reproduction. The secondset of polyps, the short-stalked reproductive ones, or nurses (Fig. 7 /), have lost their tentacles and theiroral openings are closed. On the other hand, manybuds arise from the wall of their gastric cavity, thatdetach themselves later on (Fig. 7 g), and develop intofree swimming Medusae that still later carry eggs.

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