On the Anatomy of Vertebrates Volume 1; Fishes and Reptiles (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1866 Excerpt: ...tubes. Similar organs Hunter placed first in the series of specimens of organs of touch in Fishes the snout of the Spotted Dog-fish (Scyllium), ' to show the manner of the nerves ramifying, as also their apparent termination in this part, each ultimate nerve appearing to terminate in the bottom of a tube or duct, the sides of whicb secrete and convey a thick mucus to the skin.'1 Jacobson compares them to the whiskers in the Cat. Besides the rostrum, these nervo-mucous organs are situated upon the sides and under part of the head, and on the fore part of the trunk; they are crowded between the masseter, fig. 132, I, and the branchial openings, ib. q, where they separate into two groups, one diverging downward, forward, and backward, to beneath the pectoral fin; the other directed upward, forward, and backward, to the occiput. 61. Organ of Touch in Hcematocrya.--In the Dermopteri, the Anguillidce, Siluroids, and a few other Fishes, with the integument wholly or in part scaleless, or with very minute and delicate scales, lubricated with mucus, the whole or major part of the external surface may be susceptible of impressions from the surface of extraneous bodies coming in contact therewith. But in the majority of the class the exercise of any faculty of touch must be limited to the lips, to parts of certain fins, or to the specially developed organs called ' barbules.' 1 xx. vol. iii. p. 55, prep. no. 1395. Such an organisation of a fold of skin bordering the mouth as implies the tactile faculty is rare in Fishes; the Cyprinoids exemplify it, and more especially many of the Indian species: also the marine family of Labroids. In the Sturgeon the lip has numerous papilla?, and more minute papilla occur on the lips of many fresh-water fishes. In the Eels th...