Comparative anatomy / by C.Th. v. Siebold and H. Stannius ; translated from the German, and edited with notes and additions recording the recent progress of the science by Waldo I. Burnett.

  • Karl Theodor Ernst von Siebold
Date:
1854
Catalogue details

Licence: Public Domain Mark

Credit: Comparative anatomy / by C.Th. v. Siebold and H. Stannius ; translated from the German, and edited with notes and additions recording the recent progress of the science by Waldo I. Burnett. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

    66/482 (page 62)
    CHAPTER II. MUSCULAR SYSTEM AND ORGANS OP LOCOMOTION. § 57. Tlie Acalephae have a distinct muscular system. Their contractile sub- stance is composed of a net-worlc of elongated, slender filaments and bands; these, in the utriculoid species, are arranged in a longitudinal and annular manner, but in those of a discoid and campanulate form they are disposed in a circular and radiate manner. In the extremely irritable tentacles and tactile filaments, the longitudi- nal fibres abound.(1) Each fibre is smooth when relaxed, but during contraction appears trans- versely wavy and plicated.® §58. The contractile and aerial natatory vesicles, which are found in the Phy- sophoridae,(1) and the movable lamellae of the Ctenophora, may well be regarded as accessory organs of locomotion. These last, which are arranged in rows upon the sides of the animal, and which by some anatomists have been regarded as respiratory organs, are not simple cutaneous lobes, but are composed of very long cilia closely united together, and the motion of which is voluntary with the animal.® 1 Will (loc. cit. p. 48, Taf. I. fig. 11) has observed in the contractile excrescences of the Eucharis, not only circular fibres and numerous longitudinal muscles, but large transversely-flattened ones, which were bound together by oblique bands. 2 Will, loc. cit. p. 47, 63, Taf. I. fig. 13, Accord- ing to Wagner (Ueber den Bau, &c. ; and Icon, zoot. Tab. XXXIII. fig. 30), the muscles of the Disoophora have always the transverse striae. The cartilaginous natatory pieces of the Siphon- ophora play a completely passive part in the act of locomotion. The swimming is exclusively per- formed by the energetic contractions of the mus- cular membrane which lines their cavity, con- stituting, therefore, a true natatory sac. See Sars Faun, littoral. Norveg. p. 42.* 1 Lately, it has been doubted if the Physophor- idae can sink and rise in the sea by means of their natatory bladders, because they cannot exhaust the * [ § 57, note 2.] For the muscular system of the Acalephae, see also Forbes (loc. cit. p. 3), and Agassiz (loc. cit. p. 236). This last-named author has described this system with full details in many genera. It is much more complex than has hitherto been supposed, and I must refer for the details to the memoir in question. contained air. According to Olfers (Abhandl. d. Bed. Akad. 1831, p. 157, 165, Taf. I.), there are two of these bladders in Physalia, one of which only has an opening. Philippi (Muller's Arch. 1843, p. 63) has found neither internal nor exter- nal opening to the bladder of Physophora tetras- ticha. In Stephanomia it would not appear, according to the description of Milne Edwards (Ann. d. Sc. Nat. XVI. p. 218, PI. VIII. fig. 1. b. 2), that this organ had an external opening. Couch (Froriep's neue Notizen, No. 273, p. 129) denies that Physalia has the power to control the air of its bladder. See also below, § 65. 2 Grant, Trans. Zool. Soc. London, 1.1835, p. 9.; Sars, Beskrivelser loc. cit. PI. VIII. fig. 18, e.*, Milne Edwards, Ann. d. Sc. Nat. XVI. p. 201, 216, PI. IV. fig. 2, 3, PI. VI. fig. 1. c.5 and Will, loc. cit. p. 9, 56, Taf. I. fig. 5. In regard to the structure of these muscles, Agassiz remarks : “ With all the power of the best Oberhuuser Microscope, I have been unable to dis- cover the slightest indication of striae on the mus- cular cells ; nevertheless, it cannot be doubted that they are voluntary muscles.” To this view I may add my own of the same nature. — Fd.