The pedigree of man - and other essays (1903) (14578049400)

Swimming bladder or air bladder of a Rhizophysa. c: External wall f: Large air bladder enclosed in an air sac f2: Tufted appendages from its inferior aspect xy: The two body layers, formed from the primary layers of the blastoderm x: Endoderm or digestive layer y: Ectoderm, or epidermal layer.

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

Text Appearing Before Image:

work of Leuckart, already referred to, on Polymorphism (p. 119), andat p. 104 of Carl Vogts essay on^the complex animal colonies (thirdpart, p. 162.) 110 THE DIVISION OF LABOR. lyces or swimming balls, o. Opening of the umbrella.t. Tactile polyps, g. Egg-forming female individuals, n.Nutritive individuals. Around one of the elastic central stems, often manyfeet in length, of the common axis are arranged hun-dreds, often thousands, of Medusae and polyps, thathave by division of labor attained very different shapesand structures. The central stem itself is no other thana very elongated simple polyp body, closed below, butexpanded above into a swimming bladder, or pneuma-

Text Appearing After Image:

Fig. 10. Swimming bladder or air bladder of a Rhizophysa. c. Ex-ternal wall. /. Large air bladder enclosed in an air sac. /2.Tufted appendages from its inferior aspect, xy. The twobody layers, formed from the primary layers of the blasto-derm, x. Endoderm or digestive layer, y. Ectoderm, or epi-dermal layer. THE DIVISION OF LABOR. Ill tophore, filled with air. This, buoyant upon the sur-face of the sea, supports the whole colony (Fig. 10.)Below this air vesicle is a double row of bell-shapedMedusae. These, by their common contractions, thatare subordinated to the will of the animals, move thewhole community through the sea, and hence take thename of motor polyps (Fig. 9 m.) Each motor polyp(Figs. 11, 12) is essentially a simple Medusa, but with-out arms, without organs of digestion or of reproduc-tion. Whilst they are formed solely for swimming,

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1903

University of Toronto

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