Zoological philosophy / by J.B. Lamarck ; translated, with an introduction by Hugh Elliot.

  • Lamarck, Jean Baptiste Pierre Antoine de Monet de.
Date:
1914
Catalogue details

Licence: In copyright

Credit: Zoological philosophy / by J.B. Lamarck ; translated, with an introduction by Hugh Elliot. 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.

    234/512 (page 138)
    Observations. This is the third main line of demarcation which has to be drawn in the natural classification of animals. We here find altogether new forms which, however, belong in general to one type, viz. the radiating arrangement of the parts both internal and external. We have no longer to deal with animals with elongated bodies, 3, superior terminal mouth, usually fixed in a polypary, and hving together in great numbers which share a common fife, but we have to deal with animals whose organisation is more complex than that of the polyps and which are not compound but always free, which have a conformation pecuhar to themselves and assume in general the inverted position. Nearly all the radiarians have tubes which draw in water and appear to be water-bearing tracheae, and in a great many of them are found pecuhar bodies resembhng ovaries. From a memoir which I lately heard read at a meeting of the professors of the Museum, I learn that a skilful observer. Dr. Spix, a Bavarian doctor, has discovered the apparatus of a nervous system in star-fishes and sea-anemones. Dr. Spix affirms that he has seen in the red star-fish, under a tendinous membrane which is suspended over the stomach Hke a tent, a plexus consisting of whitish nodules and threads, and in addition, at the origin of each arm, two nodules or gangha communicating together by a thread and giving rise to other threads which go to the neighbouring parts. Among these are two very long ones which traverse the entire length of the arm and send out branches to the tentacles. ^ According to the observations of this savant there are in each arm two nodules, a short prolongation of the stomach (caecum), two hepatic lobes, two ovaries and tracheal canals. In sea-anemones Dr. Spix observed at the base of these animals below the stomach several pairs of nodules arranged about a centre and communicating together by cyhndrical threads. These give rise to others which pass to the upper parts : he found moreover four ovaries surrounding the stomach, from the base of which issue canals which unite together and open at a point within the ahmentary ^'^ItTs surprising that the apparatus of such comphcated organs should have escaped the notice of all those who have studied the orgamsation •of these animals. , • i v If Dr. Spix is correct in what he describes ; if he is not mistaken by 1 [Tube-feet. H.E.]