No. 641] 



TBANSFORMATION OF SEX 



537 



B. The Somatic Sex Chaeacteks 



1. The Miillerian Duct. — -The oviduct first appears as a 

 dense cell cord close to the lateral margin of the kidney. 

 Alread}' in the first siimner the oviducts from the ostium 

 abdominale tuba) to the opening in the cloaca are com- 

 pletely formed. They are thin walled, contain a small 

 lumen, and run straight backwards. In the second year 

 they grow slowly and move away from the ureters. Ordi- 

 narily in the third year a large longitudinal growth 

 begins and the duct now becomes folded, as is well known 

 from the anatomy of adult frogs. 



In males which show a typical development of the tes- 

 ticles, no Miillerian ducts of any significance are formed. 

 On the other hand, such animals as first develop ovaries 

 and later undergo the transformation of sex, also show 

 regular oviducts ; and tlieso continue to grow just up to 

 the time when the transformation of sex hpo-ins. This 

 paralleUsw In fhr ]>rharl,>r <>f fhr M iil/rri.ni >lnris ninl fhr 

 gonads fl(nnsln:.< flrliiiif, pi-unf that tin ■■rtlil^" aihl 

 "ovocytes," (/rscrihrti hji tlii' icritri'. an' ni fact n nJUi 

 eggs and ovocytes (Hid tJuit the t ra nsfonihil Inn nf srr 

 is a tvell-establislied fact. 



After the transformation of sex, when the ovocytes liave 

 disappeared, the Miillerian ducts begin to shrink, but they 

 do not disappear completely, and such reduced oviducts of 

 various sizes are often found in adult male frogs. 



Kegarding the question of the relations between so- 

 matic characters and the gonads, the lateral hermaphro- 

 dites furnish most interesting information. The Miiller- 

 ian ducts are always developed in correlation with the 

 gonad of the same side. Lateral hermaphrodites show 

 always well-developed oviducts on the ovarial side and 

 smaller ones on the testicular side. The correlation is 

 therefore independent of the action of hormones. 



2. The Vesicida Seminatis amJ the Thumb Cushion.^ 

 The male somatic characters n|ipcnr diipfly in the second 

 year and always develop syninu trit ally. in lateral her- 



