410 DR. E. KLEIN. 



Female, No. 1 . . May 1 . 7 . 13 . 19 . 23 . 27 . June 2. 



Female, No. 2 . . May 21 . 25 . 31 . June 6 . 12. 



Male, No. 1 . . May 2 . 9 . 14 . 20 . 25 . 29 . June 3. 



Male, No. 2 . . May 21 . 25 . June 1 . 8 . 12. 



The Hgures indicate the day when the cuticle is raised as 

 a thin transparent film over the whole body of the animal ; 

 a slight touch brings it down in large flakes, but with a little 

 care it can be removed as a whole, that of the tail and 

 toes included. The first appearance of the shedding in the 

 above animals is noticed already after two or three days, the 

 glistening surface of the body becoming more or less dis- 

 tinctly cloudy. This gradually increases, and after a day or 

 two we notice a thin, transparent membrane becoming raised 

 over the head, dorsum, and abdomen, when viewed in profile 

 in transmitted light. This rapidly increases, and we soon 

 see the whole animal enveloped as it were in a bag formed 

 by that thin membrane, and raised above the surface of the 

 animal to a different extent in different parts. Thus, it is 

 mostly raised on the head and extends gradually hence to- 

 wards the posterior extremities. The "bag " is open corre- 

 sponding to the oral cleft, and probably the water getting in 

 at this opening gradually raises mechanically the bag from 

 the surface of the animal while this is swimming about, 

 head, of course, foremost. 



The cuticle, when shed, preserves the character of the 

 surface of the different parts of the body, the part derived 

 from the dorsum showing the uniform impressions of the 

 "wans,"" that from the abdomen showing a transverse arrange- 

 ment of these impresssions, that from the tail and head 

 being more or less smooth. 



The cuticle either shed or removed by means of a forceps 

 can be at once placed into haemotoxylin, and after staining 

 it — which it does readily — can be floated, as small segments, 

 on to a glass slide and mounted in glycerine.^ 



Under the mi(*ioscope the cuticle presents itself as a single 

 layer of beautiful transparent squamous polygonal epithelial 

 cells, each with an oval, or sometimes round, nucleus that 

 takes the staining very well. Some cells — not many — pos- 

 sess two nuclei. According to the nature of the surface of 

 the part of the body from which the cuticle is derived, viz. 

 whether smooth or with Avarts, we notice its surface either 

 smooth, or groups of cells are raised into a smaller or 

 larger convexity. 



1 The cuticle of newt thus stained is a material well suited for class 

 purposes, as it gives an abundance of permanent speciriiens of continuous 

 masses of beautiful squamous epithelial cells. 



