File:Medusae of the world (1910) (14781623912).jpg

Identifier: medusaeofworld02mayo (find matches)
Title: Medusae of the world
Year: 1910 (1910s)
Authors: Mayor, Alfred Goldsborough, 1868-1922 Mayer, Alfred Goldsborough, 1868-1922
Subjects: Jellyfishes Cnidaria
Publisher: Washington, D.C., Carnegie institution of Washington
Contributing Library: MBLWHOI Library
Digitizing Sponsor: MBLWHOI Library

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Text Appearing Before Image:
us asthe tentacles and each lithocyst contains 2 to 4 spherical concretions. Velum is well devel-oped. There are 80 to 100 simple, straight radial-canals and a narrow, circular tube. Stomachis wide and shallow, its diameter being about one-third that of the bell. The throat-tubeis short and conical and the mouth-opening is surrounded by small lappets which are asnumerous as the tentacles. The gonads are linear and are developed upon nearly the entirelengths of the radial-canals, leaving both ends free. The gelatinous substance of the bellexhibits a slight bluish tinge. The entodermal lamella is of a decided green. The entodermof the stomach, gonads, and tentacle-bulbs is milky or cream-colored. In some individualsthe entoderm of the tentacle-bulbs is of a decided orange and contains black granules. (See fig. 189.) Young medusa (plate 43, fig. 1).—The youngest medusa observed was 0.75 mm. indiameter. There were only 4 tentacles. 2 of these were quite long and possessed well-developed
Text Appearing After Image:
Fit;. 190.—.Squorea tenuis, by the author, from a medusa from Woods Hole,Massachusetts, Sept., 1907. basal bulbs, and the other 2 were rudimentary. There were 8 lithocysts, each containing asingle concretion. These were situated upon the bell-margin, very near to the bases of thetentacles. The velum was large. There were 4 radial-canals and the manubrium was asimple tube with 4 cruciform lips. As development proceeds the tentacles increase in number, and closely following themthe radial tubes grow downward from the margin of the stomach to the circular canal. Thelips increase in number much more slowly than do the radial-canals. The gonads and excretionpapilla; do not make their appearance until after the medusa has acquired 16 radial-canals.A. Agassiz succeeded in rearing the egg of this species and it developed into a small hydroid1.25 mm. in height and provided with 12 long, straight tentacles. This form is common along the New England coast of the United States from Juneuntil Oc

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