330 DR. E. KLEIN. 



enings ' are not in reality thickenings of tlie endotholial 

 cells, but correspond to our intracellular network of fibrils, 



Tourneux^ asserts that the endothelium lining the peri- 

 toneal surface of the septum cysterna? lymphatica^ niagn® of 

 batrachiau animals consists of two superimposed strata 

 of cells, a superficial one composed of a single layer of 

 hyaline, thin, non-protoplasmic plates, with or without a 

 nucleus, and a deep layer of protoplasmic cells. Tourneux 

 thinks that the superficial cells become detached after tliey 

 have lost their nucleus, atid that the lower protoplasmic cells 

 by division produce their substitutes. 



V. Ewctsky'^ maintains of the endothelium of the mem- 

 brana Descemeti of frog, pigeon, cat and calf, that its cells 

 consist of a hyaline membrane and a subjacent nucleated, 

 branched, protoplasmic cor])uscle. 



I have little hesitation in saying that the hyaline plate 

 of Tourneux and Ewetsky correspond to our ground-plate, 

 and that their subjacent protoplasmic corpuscle is identical 

 with o\xx intracellular networh in connection with the nucleus. 

 Contrary to these observers I regard both the ground-plate 

 and intracellular network as forming one individual endo- 

 thelial plate, that is to say, the intracellular network 

 connected with the intranuclear network lies embedded in 

 the hyaline ground-jjlate. 



II. The ground-substance of the mesentery is a delicate 

 connective-tissue membrane, being composed of a feltwork 

 of very fine fibrous bundles, to which are added the ordinary 

 fine elastic fibrils branching and anastomosing. But this 

 ground-substance is in our specimens, in which the other 

 elements are shown with all clearness of detail, only very 

 faint. 



III. The unstriped muscle- fibres. 



The mesentery of the newt contains a very beautiful 

 plexus of unstriped muscle-fibres. They are arranged'^ in flat 

 bundles, crossing each other, but chiefly interchanging its 

 fibres. The bundles are made up of a limited number of 

 fibrils, ranging between ten or more abreast down to slender 

 bundles of three or two fibrils. Most of the unstriped 

 muscle-fibres are included in this plexus, but there are 

 individual and couples of fibres leaving this plexus and 



' " llcclierches sur repitli. des Sereuscs," ' Journ. de ranatoiuic el dc la 

 physiologic,' Jan. et Fcv., 1874. 



2 " Uber d. Endotliel. d. Mcnibr. Descemeti," ' Untersucli. aus d. path. 

 Inst. Ziirich.,' iii, ISZ.*!. 



' Tlie description given here refers to specimens that have been well 

 spread out. Tlie arrangement naturally diflers if llic specimens arc iu a 

 more or less shruiikcMi coiuliiion. 



