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modifications of the former the modifications of the latter sometimes 

 correspond, but not always, and never necessarily. The areolar or 

 filamentous tissue is subservient simply to the mechanical support of 

 adjacent textures and to the preservation of form ; or it is present as 

 a means of facilitating motion. The capillaries represent merely 

 so many instruments for the conveyance of nutrient materials to the 

 textures, which themselves select, assimilate, and absorb. 



Modified in one way these elements are presented to us in the form 

 of mucous membrane : modified in another way, with additions sub- 

 servient to protection, motion, &c, they occur as integument or 

 skin. 



It is of the essential elements of the mucous tissue, and of certain 

 appendages to these as they occur in the skin of the Murana, that we 

 are at present to speak. The appendages alluded to are certain lay- 

 ers of fibrous tissue, which from their form and arrangement seem to 

 be in some way subservient to motion. 



Instead of considering the germinal membrane as a whole, it will 

 render our remarks more intelligible to treat separately of its inflec- 

 tions in the form of glands ; of its epithelium and its modifications ; 

 and lastly, of the layers of fibrous tissue on which the basement mem- 

 brane is placed. 



If the surface of a vertical section of the skin be examined with the 

 naked eye, it will appear divisible into two pretty equal parts ; — an 

 outer one, dark, dense, firm and semitransparent, and an inner one, 

 yellowish, loose, oily and opaque. The former part consists of the 

 epithelium, the germinal membrane, the pigment, the glands, and the 

 fibrous tissue, which collectively constitute the skin proper ; the latter 

 of a very loose filamentous tissue, the interstices of which are filled 

 with fat-globules. The loose tissue just mentioned forms the medium 

 of connexion between the skin proper and the dense white fascia 

 covering the muscles. 



Epithelium. 



The free surface of the skin is covered by several layers of epithe- 

 lial cells. Although the form, and even the constitution of these cells 

 varies according to their position on the skin, there are certain fixed 

 characters common to the whole, — characters of which the different 

 forms are simply modifications. With the exception of vibratile cilia, 

 with which a few of the cells are furnished, the following is the gene- 

 ral constitution of these bodies : — 1st, a transparent homogeneous 



