. On the anatomy of vertebrates. Vertebrates; Anatomy, Comparative; 1866. 546 ANATOMY OP VBKTEBEATES. —sebaceous, sudoriparous, and mucous follicles—may be developed in or from the derm : the epiderm may be condensed into nails, claws, hoofs, horns and horny scales. The warm-blooded are dis- tinguished from the cold-blooded classes by the non-conducting or heat-retaining nature of the superficial covering of the tegument. 360 Diagrammatic section of skin of Dsti, § 99. Teguments of Fishes.—The skin in fishes is more tensely stretched over the body, and often more closely united to the sub- jac
. On the anatomy of vertebrates. Vertebrates; Anatomy, Comparative; 1866. 546 ANATOMY OP VBKTEBEATES. —sebaceous, sudoriparous, and mucous follicles—may be developed in or from the derm : the epiderm may be condensed into nails, claws, hoofs, horns and horny scales. The warm-blooded are dis- tinguished from the cold-blooded classes by the non-conducting or heat-retaining nature of the superficial covering of the tegument. 360 Diagrammatic section of skin of Dsti, § 99. Teguments of Fishes.—The skin in fishes is more tensely stretched over the body, and often more closely united to the sub- jacent fascia or flesh, than in other Vertebrates: consequently it enjoys less mobility. The constituent fibres of the derm or corium are so disposed as to give it a laminated structure, fig. 360, a; the horizontal layers being connected by vertical sub- elastic fibres,' ib. b. The numerous papillte or processes from the skin of the under part of the head of the Sole (^Solea vulgaris) give it a villous character: other instances where the derm deve- lopes tactile pajiilloe in fishes are indicated at pp. 326,411. In the Lancelot the dermal fibres are minute, and compacted into two planes, one nearly at right angles to the other. In the Lamprey the derm consists of two layers of flattened fibres cross- ing each other at right angles. The epiderm exhibits numerovis large stellate pigment-cells. In the Eel, the epiderm is soft and thick, consisting of many layers of cells, caudate and tessellate, those next the derm showing pigment in stellar masses: the granular pigment-ceUs look like black spots in the epiderm. On removing this, narrow oblong scales, two lines 361. to three lines long, fig. 361, a, are seen imbedded in depressions of the derm. They consist of a finely reticulate car- tilage, the long axis of the meshes, which may be cells with confluent walls, running nearly parallel to the contour of the scale, as shown in the magnified section taken at the line marked in fi
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