. The biology of the frog. Frogs. THE BIOLOGY OF THE FROG. An excellent example oi flattened or squamous epithelium may be obtained in the outermost skin which is cast off during the molt. The cells of this layer are broad and ex- ceedingly thin, and show a rounded nucleus near the center. The cells of the peritoneum are mostly of the same flattened type. In the ^luvi- nar epithelium the cells are elon- gated perpendicularly to the sur- face and are usually prismatic in outline, owing to mutual pressure; such epithelium is common in the Fig. 31. —A portion of the mucous layer of the intestine.
. The biology of the frog. Frogs. THE BIOLOGY OF THE FROG. An excellent example oi flattened or squamous epithelium may be obtained in the outermost skin which is cast off during the molt. The cells of this layer are broad and ex- ceedingly thin, and show a rounded nucleus near the center. The cells of the peritoneum are mostly of the same flattened type. In the ^luvi- nar epithelium the cells are elon- gated perpendicularly to the sur- face and are usually prismatic in outline, owing to mutual pressure; such epithelium is common in the Fig. 31. —A portion of the mucous layer of the intestine. In epidermis of y?a«a//>,?;«. ,-,-,any places, as in the outer skin, s, stoma cell. there may be all transitional stages between columnar epithelium and squamous epithelium. Layers such as this which are several cells deep are called stratified epithelium. An some parts of the body there occurs a peculiar variety caned ciliated epithelium in which the cells are furnished with cilia at their outer ends. Usually such cells are colum- nar, but they may be cuboid or even somewhat flattened. Ciliated epithelium occurs in the mouth and throat of the frog, in certain parts of the peritoneal lining of the body cavity, on the inner lining of the oviducts, in the mouths of the cihated funnels of the kidney, in the ventricles of the brain, and, in early larval life, on the outer surface of the body. If the roof of the mouth of a frog be scraped with a knife and the cells removed and examined under a micro- scope, a shimmering movement may be seen on one side of each cell. This is due to the rapid movement of the cilia or fine hairlike processes on the surface. The cilia of all the cells of a particular area beat most strongly in one direction,. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Holmes, Samuel J. (
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectfrogs, bookyear1916
