Synopsis of the contents of the museum of the Royal College of Surgeons of England.

  • Royal College of Surgeons of England
Date:
1862
Catalogue details

Licence: Public Domain Mark

Credit: Synopsis of the contents of the museum of the Royal College of Surgeons of England. Source: Wellcome Collection.

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

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    Class Tunicata. The Tunicata are unsymmetrical shell-less molluscous animals of somewhat lower organization than the Mollusca generally. Their body is enveloped in a coriaceous integu- ment or tunic, whence their name. They are exclusively marine, and widely distributed from the arctic to the tropical seas, and occur both fixed in the shallow zones and floating in the open seas. Some are simple, and others united into compound organisms. Owing to the soft nature of the animals of this class, there is little in illustration of them in this department of the Museum ; but the appearance of some of the more interesting forms can be studied in the Lower Gallery of the Middle Museum (Series of Natural History in spirit). Class Brachiopoda. The Brachiopoda are bivalve Mollusks, which by their or- ganization connect the Bryozoa and Tunicata on the one hand, and the Lamellibranchiata on the other. The valves of the shell are placed, one upon the dorsal, the other on the ventral surface of the animal. The dorsal valve is usually the smallest, and the ventral valve the largest; the latter gene- rally having a prominent beak by which it is attached to some rock or other submarine object, as in Thecidium and Crania, or else a perforation through which a pedicle for attachment passes. The general form and the resemblance of this orifice to the hole through which the wick protruded in the antique lamp, has caused the name of “ Lamp-shell ” to be given by the old naturalists to several members of this class. See Tercbratula and Waldheimia, E 44, 45, and 46 [F.]. The Brachiopoda are widely distributed in space, being- found both in the polar and tropical seas; they range from shallow water to the greatest depths, but are mostly found in the deep sea. They are as equally distributed in time, being found throughout all the sedimentary deposits, from the oldest to the most recent. Upwards of 1000 fossil species have been described, of which the greater number belong to the British