101 



gelegene Epithelbildung, die etwa 9ö f.i breit und 80 — 100 ,u lang ist 

 und teilweise so stark über die normale Epidermis hervorragt, daß 

 sie mit dieser nur durch eine schmale Brücke zusammenhängt. Die 

 Abbildung (Fig. 51) zeigt die eigenartige Form sehr deutlich". 



Schmidt also found inguinal epidermal thickenings, which may be 

 homologous to these, in two of his embryos. In describing embryo 

 IV (35 mm) he says: "Von demselben Embryo habe ich dann noch 

 beiderseits die Regiones hypogastricae zur Anfertigung von Querschnitt- 

 serien verwendet. Die linke Seite ist unbrauchbar, weil die Schnitte 

 zum größten Teil ihres Epithels beraubt sind. Doch findet sich auch 

 hier unter den fragmentarischen Epithelresten eine hügelförmige An- 

 lage, die in 2 Schnitten ä 30 (.i nachweisbar ist und eine Länge und 

 Breite von etwa 50 — 60 (.i besitzt." 



On the right side of the same embryo and in the same region he 

 finds three small lens-like Anlagen which resemble the normal Anlagen 

 found in the pectoral region more than those just described. Again 

 in his embryo VII (ÖO mm) he finds "2 hügelförmige Anlagen von 

 50 — 60 jf< Breite und Länge" in the right inguinal region. 



Tables III and IV give in detail the location , size and form of 

 the Anlagen in Piper I while Diagram II, made from the wax recon- 

 structions, represents graphically their arrangement. 



Conclusions. 



There seems to be no doubt as to the temporary presence in man 

 of these epithelial thickenings. Their significance, however, is more 

 difficult to determine. At the beginning of this paper Hugo Schmidt's 

 reasons for giving them phylogenetic importance as the Anlagen of 

 supernumerary mammae, were presented. There are some objections 

 to this interpretation. 



I. If supernumerary mammae in adults are a case of atavism 

 (and this explanation of Darwin's seems to be the most tenable one) 

 then we ought not to expect to find more supernumeraries in any adult 

 than are found normally somewhere in its ancestral series. This law 

 holds good in all observed cases. For instance Wiedersheim (20) 

 cites as an extreme instance a soldier with eight supernumeraries but 

 the pig, as well as many other mammals, exceed this number in normal 

 mammae. Now there are forty of these Anlagen in Piper I and also 

 an equal number in Schmidt IV but no mammal living or extinct 

 having so many mammae, is known. The actual number of structures 

 therefore goes against the hypothesis of their being atavistic remains 

 of mammae. 



