A history of the British zoophytes / by George Johnston.

Date:
1838
Catalogue details

Licence: Public Domain Mark

Credit: A history of the British zoophytes / by George Johnston. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    When expamlecl, the superior division of the body seems formed of fleshy bnrs placed in a reticulated manner, and lined with a fine membrane. From perforated warts, placed without order on the outer coat, issued white filamentose substances variously twisted together: I have observed a similar body ejected from the mouths of all the species of this genus which have fallen within my notice.” Adams. The following moi’e detailed description of this very interesting species is by Dr Coldsti’eam. “ General mass of the animal flattened and extended ; thickness at the oral disc three-tenths of an inch, di- minishing towards the circumference of the base; longest diameter of the base about three inches ; margin minutely crenated ; colour of the body, near the base, reddish brown, passing gradually into a light cream colour towards the oral disc; whole surface striated longitudi- nally with alternate opaque white, and translucent bluish lines, and marked iri’egularly with bright reddish-purple spots. These spots are confined to the outer coat, which is easily peeled off. That be- low it is of a pink colour, and is marked with the striae, which shine through the outer coat. Oral disc of an elongated oval form, white, and bearing on its outer margin numerous rather short tentacula ar- ranged in three or four irregular rows : tentacula shorter than the body, acuminated, white, each marked with a faint streak of brown ; mouth large, oval; lips white, contracted into folds; internal sur- face of the stomach marked with numerous white striae. Base fixed to a thin horny expansion attached to the apertures of va- rious dead shells, such as Trochus cinerarius and T. Magus, and form- ing, as it were, an extension of the body-whorl of the shell in a spir- al form. Over this, the Actinea is spread entirely, and covers also more or less of the shell. Its oral disc is uniformly situated close to the inner lips of the horny case. The aperture of the case is accu- rately surrounded by its body, the margins of the opposite sides of which meet, and are closely applied to one another at the middle of the outer lip of the aj^erture, whence they run upwards towards the old shell, where they generally separate again, leaving its apex un- covered.” ■“ The horny membrane to which the Actinia is attached, covers, for the most part, nearly the whole of the external surface of the .old shell to which it is fixed, and from the circumfe- rence of its aperture, is prolonged into a large hollow expansion, re- sembling in form, and occupying, relatively to the shell, the place of, a ventricose body-whorl. Its substance is of a uniform thickness throughout its whole extent, of a greenish-brown colour, translucent, having both surfaces irregularly wrinkled transversely. In a recent state it is quite flexible, but when dried it is brittle. It takes fire and burns readily, leaving a very small residuum, which does not ef-