klaatsch's views 53 



milk-gland buds, led to Klaatsch's further 

 development of the views of the great Heidel- 

 berg anatomist. 



In 1883 Klaatsch, completely refuting Rein's 

 theory, succeeded in showing from observa- 

 tions on a large number of marsupial young 

 that the nipple-pouches actually spring from 

 the knob-shaped primordia, and that it is from 

 the bottom of these pouches that the milk 

 glands bud out. In a second work (1891) he 

 tried also to explain the genesis of the mar- 

 supium by means of the mammary-pouch 

 theory. He found that in the case of the fully 

 developed Trichosurus female, the two nipples 

 were situated in pouch-shaped depressions, the 

 lateral edges of which coincided with the edges 

 of the marsupium (Fig. 18). These pouches 

 are the structures which we have distinguished 

 {antea, p. 17) as marsupial pockets. Klaatsch 

 made the mistake of taking them for nipple or 

 mammary pouches, an almost inconceivable 

 mistake, since in the female the nipples were 

 already present, and it was, of course, impos- 

 sible that nipple pouches should exist after 

 they had been everted. But he came to this 

 conclusion, because it fitted in excellently with 



