Zoological classification : a handy book of reference with tables of the subkingdoms, classes, orders, etc., of the animal kingdom, their characters and lists of the families and principal genera / [Francis Polkinghorne Pascoe].

  • Francis Polkinghorne Pascoe
Date:
1880
Catalogue details

Licence: Public Domain Mark

Credit: Zoological classification : a handy book of reference with tables of the subkingdoms, classes, orders, etc., of the animal kingdom, their characters and lists of the families and principal genera / [Francis Polkinghorne Pascoe]. Source: Wellcome Collection.

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    With a calcareous polypary. Polypary, when present, chitinous ... With a hydriform trophosome. Not permanently attached Permanently attached. No hydrotliecae nor gonangia Hydrothecm and gonangia Without a hydriform trophosome HyDROCORALLIN/E. Electiieroblastea. Gymnoblastea. Calyptoblastea. Haplomorpiia. Order I. ELEUTHEROBLASTEA. IIydrida. Gymnochroa. Pcecii.omorpiia. Hydrosome consisting of a single polypite, not permanently fixed. Nutritive huds at maturity discharging themselves and then growing independently as free organisms. Only one genus is known, containing the common Hydra viridis and two or three other species. They are found in fresh water, and if cut up each piece will develop in a few hours into a perfect animal. The body is tubular, capable of great extension; and its proximal end is furnished with a hydrorhiza, by which it can attach itself at will to any foreign body ; the opposite end is pro- vided with tentacles, by which it secures its prey. In the sexual mode of reproduction ova are formed near the fixed end, and spermatozoa, which are liberated at the same time, are formed at the base of the tentacles. Hydra is sometimes monoecious, sometimes dioecious. Hydrides. Hydra. Order II. GYMNOBLASTEA. Coryxida. Tubularina. Athecata. Tubulariax Hydroids. Polypites aggregated. No hydrotheem nor gonangia present, either for the polypites or the gonophores. These are delicate plant-like marine organisms, except Cordylo- phora, attached to various foreign bodies, and developing buds [gonophores], which often becoming detached, float away into a free existence [planoblasts, or gonozoids], and are then known under the general name of Medusae. The Medusoid gonophore is composed of a swimming-hell (nectoealyx) with its inner margin produced into a delicate mem- brane called the “velum,” its outer margin bearing the tentacles.