Ryder.] ^^^ [Oct. 4, 



smooth and iongitudiaally disposed muscular fibres, tliougli it is to be 

 borne in mind that just beneath the closely grouped globular or flask - 

 shaped glands there occurs the outer non-fibrous and granular layer of 

 the corium which contains no cellular elements. This non-nucleated layer 

 is followed by the rather thick fibrous corium, containing connective-tis- 

 sue cells. This layer of fibrous matter has a horizontal disposition and the 

 included cells are much flattened, and like the fibrous tissue are parallel to 

 the surface. Then follows the second or deepest layer of pigment, and in 

 this latter the principal dermal blood vascular network is embedded. This 

 deeper vascular network, however, joins a much less developed and more 

 superficial vascular network of capillaries, which ramifies just beneath the 

 epidermis, their junction being elTected at intervals by means of small 

 vessels, which penetrate the inner fibrous and outer granular layers of the 

 corium. This outer capillary plexus forms a mesh of vessels just below 

 the epidermis. This outer ' plexus also forms more or less complete 

 plexuses about the globular glands already spoken of. The blood vascular 

 plexus is incomplete over the deeper ends of the glands, but narrow 

 lymph channels and spaces surround them. These lymph spaces are 

 probably continuous with the intercellular spaces between the deeper 

 strata of epidermal cells, and communicate with the larger intercel- 

 lular lymph passages which are very obvious between many of the cells 

 of the second or penultimate layer; the direct outward communication of 

 these wider intercellular superficial passages seems, in lact, to be shut otf 

 by the presence of the outermost layer of epidermal cells, the edges of 

 which are closely joined together. The only remaining elements of the 

 skin to be mentioned is the outermost or superficial layer ot pigment 

 cells just beneath the epidermis. The most superficial blood vascular 

 plexus is in close relation to this outer stratum of pigment cells; these fre- 

 quently extend over the sides of the glands immediately overlying their 

 coat of smooth muscular cells. In densely pigmented regions the pigment 

 cells frequently form a reticulum under the epidermis and over the glands, 

 the processes of the cells loaded with pigment granules blending so as to 

 produce the appearance of a fabric with irregular meshes, this meshwork 

 being depressed at close intervals in the form of a minute reticulate sack 

 into which a gland depends in each instance. 



The w^alls of the glands in sections are composed of clear cubical cells 

 containing a bright nucleus and two or more nucleoli. 



This description is drawn from the appearance presented by sections of 

 the skin of the common edible frog of the United States, Rana cateshiana , 

 and from the writer's observations upon other forms; the account given 

 applies in general terms to a great many other batrachian forms. 



2. The next group (Reptilia) does not possess ejiidermal glands except in 

 a few instances, over a fe\Y very limited areas of the integument. The dis- 

 cussion of tlieir integument in this connection would therefore be of no 

 interest, since the integumentary glands have for the most part been lost 

 or suppressed. 



