48 R. R. HUMPHREY. 



Champy, indeed, states his belief that the number of lobes is not 

 at all dependent upon the age of the male. 1 In Dcsmognathns, 

 however, the evidence shows clearly that the sexually immature 

 male, regardless of size and vigor, possesses only a simple testis 

 i.e., only one lobe is present. The multiple testis, then, must arise 

 by the addition of other lobes through growth processes following 

 sexual maturity; in other words, the age of the animal must be 

 considered as a factor. 



Preceding investigators, so far as can be ascertained, have 

 merely noted the occurrence of the multiple testis and speculated 

 as to its possible correlations. The origin of the numerous en- 

 largements or lobes has not been adequately investigated, and it is 

 to their origin and development that we must turn if we are to 

 fully appreciate their significance. Spengel ('76) makes the brief 

 statement that the numerous lobes of a multiple testis arise as the 

 result of the complex growth, degeneration, and regeneration proc- 

 esses of the organ. 2 This statement, properly elaborated, fur- 

 nishes, I believe, the correct interpretation of these structures. 

 The pattern of the spermatogenetic processes, in other words, ex- 

 plains the multiple testis. It is clearly not a structure of seg- 

 mental origin; its correlation with the body size or body form of 

 the species or the individual of the species can not be established. 

 It is, as I shall attempt to show by a discussion of the urodele plan 

 of spermatogenesis, a structure arising from the combined opera- 

 tion of three factors: (i) the slow movement of the spermato- 

 genetic "wave"; (2) the delayed regeneration of the emptied 

 lobules at the close of the spermatogenetic cycle; (3) the age of the 

 animal i.e., the number of sexual cycles through which the two 

 first-named factors have been operative. 



1 An earlier French worker, Duvernoy ('51), according to Spengel, reached 

 a similar conclusion. Spengel (p. 65) says: " Er glaubt, die Zahl der Ab- 

 schnitte sei allein abhangig von der Brunst, da er keine constanten Altersun- 

 ter.schiede zu entdecken vermochte." 



Spengel (p. 65) says : " Die eingehendere Erorterung dieser Frage muss 

 ich bis zur Darstellung der Entwickelung und des Wachsthums verschieben 

 Whether Spengel ever published a more detailed explanation of the 

 multiple testis, as the foregoing quotation shows he proposed doing, I am un- 

 able to state. No reference to any later work by him on the amphibian testis 

 has been encountered in the literature, although his first publication, " Der 

 anatomische Bau des Urogenitalsystems," is often extensively quoted. 



