1 1 2 STRONG. [Vol. X. 



differences evidently depend upon differences in the structure 

 of the skin, in the thickness of its different layers and the 

 form and arrangement of the epidermal cells. The branches 

 break up in the deepest layer of the cutis, bend at right angles 

 and form a heavy, coarse plexus of nerve fibres extending 

 parallel to the surface. From this plexus one or several fibres 

 pass vertically through the middle layer of the cutis and in the 

 superficial layer break up into terminal arborisations, the fibrils 

 of which pass into the epidermis, there to ramify still further. 

 The course and configuration of these ramifications is corre- 

 lated in a general way with the shape of the epidermal cells. 

 In passing through the middle layer of the cutis the vertical 

 fibres give off branches at right angles which course along 

 between the dense parallel strands of connective tissue which 

 constitute this layer. The endings in the different layers 

 appear to be always free and intercellular. The precipitate 

 formed on the surface often interferes with following them to 

 their final terminations. 



Immediately beneath the middle layer of the cutis, and still 

 more abundantly in the superficial layer immediately beneath 

 the epidermis, a number of dark bodies are present (Fig. 4, x), 

 usually with a smooth oval outline, and are, apparently, a 

 species of pigment cell. While the nerve fibres now and then 

 lie close to these, there is no connection between the two. 

 I have not found any cells, such as those described by Eberth 

 and Bunge (16) in the foot of the frog. While negative evi- 

 dence, especially with Golgi preparations, is far from conclusive, 

 yet I think, judging even from their own figures, their results 

 are open to the criticisms made upon them by Van Gehuchten 

 (27). 



2. The Facialis aftd Acttstictis {Auditory). 



The Facialis and Acusticus present even greater dif^culties in 

 the tadpole than in the Urodela. In the latter the exits of the 

 Acusticus, and what is here called the doi'sal VII, are quite 

 distinct. The latter is considerably reduced in the tadpole and 

 in proportion as it is reduced the Acusticus is increased, the 

 exit of the VIII being extended so much dorsad that it and 



