Beiträge zur Lehre von den Eingeweiden der Hatteria punctata. 185 



The epithelial cells. In the Tortoise they are clistinctly 

 columnar. A double line of demarcatiou is often seen on the 

 summits of the epithelial cells. 



Reticulum. — On viewing frora the surface the epithelium 

 of the vesicle iu the thyroid g-land of the Tortoise hardened in 

 chroraic acid, a dclicate network is seen runniiig- between the 

 individual epithelial cells, which stains darkly with haematoxylin. 

 This reticulum, which is probably formed by coagulated inter- 

 cellular substance, is seen to be thickened at intervals. — In 

 spirit, and in osmic acid preparations, this reticulum is also ob- 

 served in a surface view. In a profile view of the epithelium 

 of the Tortoise there are seen at intervals amongst the epithelial 

 cells, narrower cells with much elongeted nuclei, which latter 

 take the hämoxylin stain more darkly than the nuclei of the 

 epithelial cells. — Probably these are more or less branched 

 cells, which are situated in the swollen part of the reticulum. 



Basement membrane. —In the osmic acid preparation 

 of the Tortoise, where the wall of a vesicle happens to be cut 

 obliquely, lying outside the epithelium, is seen the nucleated 

 membrane formed by the endothelial cells of the lymphatics, 

 and on this are observed tine wavy Striae, which are evidently 

 due to a delicate lager ot connective tissue interposed between 

 the endothelium and epithelium in which the capillary blood 



vessels ramy I have not observed any other form of 



basement membrane, nor have I been able to detect by macera- 

 tion in Müller's fluid, any basement membrane resembling the 

 „Drüsenkörbe" described by Boll. 



Contents. — The following are the chief constituents 

 of the Contents of the vesieles: 



a) Homogenous or granulär material (Colloid), 



b) Red blood-corpuscles, 



c) Colourless blood-corpuscles, 



d) Rounded masses, which stain darkly with haematoxylin 

 or of a bright yellow colour with picrocarminate of am- 

 monia (Schildkröte scheint nicht untersucht worden zu sein), 



e) Crystals and Pigment (erstere bei der Schildkröte, das 

 zweite beim Frosch angegeben). 



Parenchym. Besondere Angaben für die Schilddrüse 

 fehlen. In Bezug auf die Schilddrüse vom Hund sagt er: „I 



