104 



I. That the Hugo ScHMiDT-Anlagen certainly have some relation 

 to the mammary apparatus is conceded on all sides. Their early dis- 

 appearance ontogenetically indicates that, if they are phylogenetically 

 significant at all, they must date back to something quite as primitive 

 as the marsupial pockets of Bresslau. Furthermore the temporary 

 appearance of these structures in man occurs at the time when the 

 true milk gland is passing through the knob phase ("kolbenförmig", 

 Rein). This is also the phase of development which the milk points 

 have reached in Didelphys according to Bresslau when these 

 marsupial pockets develop and disappear. Therefore so far as the 

 milk points themselves can serve as a criterion of time these epithelial 

 structures are contemporaneous with the marsupial pockets. 



II. Their general locality, scattered around in the immediate vi- 

 cinity of the milk points but largely above and axillary to the same, 

 is easily explained on the supposition that they are relics of marsu- 

 pial pockets. This is very evident on the left side of Piper II (Dia- 

 gram II). The fact that the marsupial pockets in the opossum are 

 mostly inguinal in position while these epithelial thickenings iu man 

 are mostly pectoral, is not a serious obstacle to their homology. In 

 both cases they are satellites to the milk glands and the important 

 fact is their location with reference to the milk glands rather than 

 with reference to the entire body. 



III. The fact that many of these Anlagen are wider than they are 

 long is better explained by imagining them Ito be the relics of a broken 

 ring (marsupial pocket) extending around the milk point than as relics 

 of a broken longitudinal line (mammary line). 



IV. When all the Anlagen which have been described (see Table V) 

 are arranged according to their form they make a series such 

 as is shown in Table VI. The sequence of forms in this table corre- 

 sponds with the sequence in the early phases through which the milk 

 point itself passes, as first shown by Rein (13). In no case are the 

 Anlagen found as far advanced as the true milk Anlagen and the great 

 majority of them do not get beyond what may be compared with the 

 very earliest stages of the true milk Anlagen. It will be seen that the 

 prevailing type is that of an ingrowth of epithelial cells ("zapfen- 

 förmig") without any corresponding elevation over the surface. This 

 is exactly what Bresslau represents for the cross-section of his mar- 

 supial pockets in Didelphys. If these epithelial thickenings are 

 Anlagen of supernumerary mammae and take their origin from a ho- 

 mologous source as the true milk points it would naturally be expected 

 that they would pass through the same general phases of development. 



