. The biology of the frog. Frogs. IX THE SKIN 185 mucus glands, and less uniformly distributed over the sur- face of the body. They are more numerous on the dorsal side of the body and hind legs, and they are especially abundant, and unusually large, in the lateral dermal plicae. According to Junius, they occur on all parts of the skin, although they may be comparatively scarce in certain situa- tions. Like the mucus glands they possess a muscular and a connective tissue coat outside the layer of epithelium. M. G M. G. ^5Z T>*>.. *wf^.vK> .. ^^l^s »p'~ ^"^: * _• . *, X £*1*X P. G
. The biology of the frog. Frogs. IX THE SKIN 185 mucus glands, and less uniformly distributed over the sur- face of the body. They are more numerous on the dorsal side of the body and hind legs, and they are especially abundant, and unusually large, in the lateral dermal plicae. According to Junius, they occur on all parts of the skin, although they may be comparatively scarce in certain situa- tions. Like the mucus glands they possess a muscular and a connective tissue coat outside the layer of epithelium. M. G M. G. ^5Z T>*>.. *wf^.vK> .. ^^l^s »p'~ ^"^: * _• . *, X £*1*X P. G P. G FlG. 48. — Section across a dermal plica of Rana esculenta. M. G, mucus glands; P. G, poison glands; the granular epithelium has an indefinite outline and shows no cell walls. (After Gaupp.) The chief differences in the two types of glands, with the exception of size and the thickness of the tunics, lies in the secreting cells. Engelmann described the epithelium as consisting of cylindrical cells nearly filled with granules. The boundaries of the cells apparently disappear under cer- tain conditions of secretion, the epithelial lining forming a continuous irregular layer of protoplasm (Gaupp). The secretion of the poison glands is a whitish fluid with. 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. (Samuel Jackson), 1868-. New York, London, Macmillan
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Keywords: ., bookauthorholmessamueljsamuelja, bookcentury1900, bookdecade1910
