FIG. 24. Transverse section 

 through normal trout embryo, a con- 

 siderable distance in front of the vent. 

 Compare with Fig. 27 (union by pos- 

 terior part of body). Other references 

 under PI. I. fig. i. (xi4.) 



$&-.; *..'.i>; ^ ; - ; 



FIG. 27. Transverse section corresponding with Fig. 24, 

 but through a double monster of the type illustrated in 

 PL II. fig. 10. Figs. 28, 29, and 31 are from the same 

 series. At this level the two intestinal canals are widely 

 separated. For relations of Wolffian ducts, etc., see pp. 

 22, 23 and PI. XIX. figs. 76-79. (xi4.) 



FIG. 25. Transverse section as in 

 Fig. 24, but a little further back. 

 Compare with Fig. 28 (union by pos- 

 terior part of body). Other references 

 under PI. I. fig. i. (xi4.) 



FIG. 28. Transverse section of the same double monster 

 as in Fig. 27, but a little further back in the series. The 

 intestine is now single, but has two mesenteries. The Wolftian 

 bodies and ducts are coming together by their inner, or 

 adjacent, sides. Compare with Fig. 25 (normal). Other 

 references under Fig. 27. (xi-|.) 



FIG. 26. Transverse section, as in 

 the two preceding figures, but passing 

 just in front of the vent. The Wolffian 

 ducts have opened into the bladder, 

 which is seen lying dorsal to the 

 rectum. Compare with Fig. 29 (union 

 by posterior part of body). Other 

 references under PI. I. fig. i. (xi4.) 



FIG. 29. Transverse section through same double mon- 

 ster as in Figs. 27 and 28, but further back in the series. 

 Compare with Fig. 26 (normal). The adjacent Wolffinn 

 ducts have opened into a first bladder, while the outer ducts 

 have not yet reached the second one, which lies posterior to 

 the other. These relations are explained on p. 23. Other 

 references under Fig. 27. (xi4- ) 



PL. VI. 



