508 NICHOLAS ZOGRAFF. 



the tissue has been split asunder into its component parts by 

 means of fine needles, after it has been macerated for thirty- 

 six hours in weak alcohol. 



On its outside the cutis is covered with an epidermis of 

 many layers (figs. 7, 8 and 9). This epidermis consists of 

 numerous very small cells, scattered among which there is a 

 quantity of mucous goblet-like cellules. 



The latter are not seen in sections kept in alcohol and pre- 

 pared in paraffine or soap, but they are well observed in 

 sections prepared in osmic acid, and embedded in the white of 

 egg according to the method of Kalberla. In such sections 

 we observe that the number of goblet-like cells in the 

 epidermis is very great, and that consequently these cellules 

 can let out a considerable quantity of slime or mucus which 

 covers the labyrinthine apparatus. The bottom of such cells 

 is fast set in between other cells of the epidermis, and that 

 is the reason why when teazed they come out with irregular 

 edges (fig. 3) ; one can observe in their goblet-like cavity a 

 fine irregular protoplasm network and also a slime or mucus, 

 the traces of which are seen outside the cell. 



Having described the construction of this apparatus, so com- 

 plicated and entangled externally, but so simple in its micro- 

 scopic structure, I now return to its functions. 



The first view of the strongly-developed capillary networks 

 which are separated from the exterior by a fine epithelium of 

 two or three layers and have arterial and venous vessels, and 

 let only one or two corpuscles of blood through their cavities, 

 makes us suppose that these capillary nets are the principal 

 part of the organ. If, on the other hand, we remember that 

 the organism of labyrinthine fishes must have adaptations 

 for the characteristic, partly terrestrial or amphibious mode of 

 life which is described by all authors, we shall have to seek 

 in the organism of these fishes for such adaptations, and we 

 must hope to meet with organs which will admit oxygen to 

 the blood, not only from the air dissolved in water, but also 

 from the atmosphere. The labyrinthine apparatus is such an 

 organ. To establish a decisive view as to the physiological 



