THE MULTIPLE TESTIS OF URODELES. 59 



length of time that it is in Dcsmognathus, the animal would, of 

 necessity, pass an interval of one or more years of sexual inactivity 

 before reproduction again became possible. Such a condition, of 

 course, does not exist in any known urodele. 



Even in an animal possessing the spermatogenetic pattern requi- 

 site for the production of a multiple testis it is further essential 

 that considerable time elapse after sexual maturity before a second 

 testicular lobe is developed, and, following this, still another inter- 

 val before the appearance of a third. All the evidence from Dcs- 

 mognathus is contradictory to Champy's assertion that age is not 

 a factor, and that a male one year of age may possess testes of 

 several lobes. Sexually immature males with more than one lobe 

 are unknown to the writer. Large, heavy-bodied males invariably 

 have multiple testes ; these males, however, are always sexually 

 mature, as shown either by the presence of spermatozoa or the 

 occurrence in the testis of degenerating lobules emptied in a pre- 

 vious sexual cycle. Further, these large, heavy-bodied males, when 

 one takes them in large numbers from their natural environment, 

 must also average older than slender-bodied males of half to two 

 thirds their body length taken from the same environment. Males 

 of this last class average a smaller number of testicular lobes. In 

 short, the younger the animal, the smaller the number of lobes that 

 will be found to have developed. 



As previously stated, the writer does not consider that the num- 

 ber of lobes is associated with body size alone, as claimed by 

 Champy. Since, however, body size is to a certain extent corre- 

 lated with age, an incidental correlation between lobe number and 

 body length may be expected as a result. Examination of Desnwg- 

 nathus males shows some sexually mature animals to be only of 6 

 to 7 cm. total length, while the largest males measure 10 to 12 cm. 

 A graphic representation of the relation of size to the form of the 

 testis is presented in chart II. For graph A, stages i to 14 in the 

 development of a multiple testis, taken from chart I., are used as 

 abscissse, and the corresponding average body lengths of the males, 

 as given in Table I., are used as ordinates. It will be noted that 

 up to stage 5 there is a fairly gradual increase in body length, along 

 with the increase in the number of lobes. Animals at this stage 



