DEVELOPMENT OF THE FAT-BODIES IN RANA TEM- 

 PORARY. A CONTRIBUTION TO THE HISTORY OF 

 THE PRONEPHROS. 



By Arthur E. Giles, B.Sc. (Lond.), M.B., Ch.B. (Vict.), 



Piatt Physiological Scholar, Owens College, Manchester ; House Surgeon, 

 Manchester Boyal Infirmary. 



[With Plate IX.] 



It has generally been held, since the researches of von Wittich, 

 that the fat-bodies, or corpora adiposa, in the frog and allied 

 Amphibians, are derived from the genital organs by a process of 

 fatty degeneration in the anterior end of the primitive genital ridge. 



Von Wittich himself says,* " they (the fat-bodies) have not at 

 any time any connection with the Wolffian bodies, nor with the 

 kidneys or their ducts." And again, " the genital organs become 

 constricted into an anterior and a posterior part, of which the anterior 

 becomes the fat-body, and the posterior the genital organ." 



This investigation, conducted in the biological laboratories of 

 Owens College, was begun with the intention of ascertaining if these 

 views of von Wittich were correct. But its progress showed that 

 the mode of development of the fat-bodies is very different from 

 what von Wittich thought, and that the changes which take place 

 are of a very interesting nature. 



On dissecting a tailed frog, as represented in Fig. 1, the fat-bodies 

 were scon already beginning to take on the loboso form which 



* " Beittage ZIM morphologisclu n urid lii.st,oli,»isdicn Kntwic.krliiii^ <lcr i I.i iii mill 



(. chlecbte Werkzeuge der nackten Amphibien," "/cits, fur wi.s.s. Zool.," 4to 

 Band, 1853, pp. 148, 149. 



