GLANDULAR EPITHELIUM AND DIVISION OF NUCLEI. 411 



The thickness of the cells is about 0*004 mm., the breadth 

 about 003 to 0'04 mm. 



The cell-substance is generally not deeply stained, and 

 contains few pigment granules around the nucleus. 



As a rule, the cells forming the convex sections, i.e. 

 corresponding to the surface of the warts, are deeper stained 

 than those between ; the cells of the cuticle corresponding 

 to the front part of the head are also, as a rule, more deeply 

 stained than those of the neck. Some of the cells contain 

 one or more larger or smaller holes (vacuoles), probably signs 

 of degeneration ; they were noticed in the superficial cells 

 of other amphibia by F. E. Schullze and Eberth. The cells 

 are separated by a very well marked, highly refractive linear 

 interstitial substance, either straight or more or less curved 

 and sinuous. The cells possessing a certain thickness, and 

 their lateral margins not forming quite a vertical plan, 

 but are more or less slanting one way or the other, it 

 follows that when looking at the cuticle from the surface 

 Ave see that the separating lines, viz. those marking the 

 margins of the individual cells of one surface do not 

 coincide with those of the other. In connection with this 

 cuticle we notice numerous short tubes, some thin, others 

 broad, opening with a small mouth between the cells. Their 

 length is about 0*04 mm., and their breadth is about 0"018 

 or 0*027, according to Avhether they belong to the narrow or 

 broad variety. These tubes are made up of a transparent 

 membrane finely and indistinctly longitudinally striated, and 

 showing a compressed nucleus at or about the opening. 

 These structures represent, therefore, one or two flattened 

 cells rolled into a tube. In some instances I can recognise the 

 linear suture. I need hardly add that these tubes are the ducts, 

 or part of them, of the numerous glands of the skin, shed 

 simultaneously with the cuticle. The length of these tubes 

 being less than half the thickness of the whole epidermis, 

 even of hardened specimens, it foUoAvs that part only of the 

 glandular ducts is shed with the superficial layer of the 

 epidermis. 



In connection with these ducts there may be seen occasion- 

 ally one, two, or three surrounding epithelial cells removed 

 from the subjacent layer of the epidermis. There can be, 

 therefore, no doubt that the most superficial layer of the epi- 

 dermis, whether still belonging to this latter or already 

 separated, is composed of nucleated squamous epithelial cells, 

 not of non-nucleated horny '■' cuticular excretions," as 

 maintained by Leydig (1. c.) for all amphibia. 



Seeing then that there exists in the adult newt a conti- 



