. The biology of the frog. Frogs. REPRODUCTIVE ORGANS AND FAT BODIES 223 attain their maximum, after which they decrease in size dur- ing the fall and less rapidly during the winter. In Rana esculenta, according to Ploetz, the testes vary little in size in different months. This is, perhaps, due to the fact that during most of the year all stages of spermatogenesis may be met with in some of the tubules. The interstitial substance between the tubules increases in Rana fusca from March to September. There is a storage of fat and pigment during this period which later disappears (Ploetz, Friedma
. The biology of the frog. Frogs. REPRODUCTIVE ORGANS AND FAT BODIES 223 attain their maximum, after which they decrease in size dur- ing the fall and less rapidly during the winter. In Rana esculenta, according to Ploetz, the testes vary little in size in different months. This is, perhaps, due to the fact that during most of the year all stages of spermatogenesis may be met with in some of the tubules. The interstitial substance between the tubules increases in Rana fusca from March to September. There is a storage of fat and pigment during this period which later disappears (Ploetz, Friedmann). In Rana esculenta there is most interstitial substance around o 0 April June July Sept. March May August Fig. 72.—Seasonal changes in the size of the testes of Rana temporaria. Natural size. (After Witschi.) those tubules in which the process of sperm production is most rapidly going on. The Fat Bodies (Corpora Adiposa).—The fat body is a yellowish organ lying just in front of the gonads. It is fur- nished with a number of finger-like processes whose number varies not only in different individuals but also in the same individual at different times. In the male the fat body is broadly and closely attached to the anterior end of the testis. In the female it is less closely attached to the gonad than in the male. The fat bodies serve as a sort of storehouse of nutriment. They undergo great changes in size during different seasons of the year, as has been described in a previous chapter. The histological phenomena wThich accompany these changes. 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 : The Macmillan company
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