Zool.— Vol. I.] RITTER—DIEMYCTYLUS TOROSUS. 93 



also furnished with a dark, dirty pigment that does not exist 

 here at other times. The glands in this area are peculiar 

 to it also, but whether they are the ordinary epidermal glands 

 modified for the occasion only, or are permanently different 

 from the latter, I do not know. These patches are rather 

 transient and disappear very soon after the culmination of 

 the reproductive activity. As a rule the soles of the hands 

 and feet of the males become black, and the tips of the 

 digits capped with black at this season, but this character 

 is apparently less constant than are the others mentioned. 

 Figure 10 illustrates the several points described. Prof. 

 Cope's unqualified statement that "the epidermis on the ex- 

 tremities of all the digits is horny," is an error, probably 

 induced by the author's having observed the condition here 

 described. Ordinarily the epidermis of the toe tips does not 

 differ from that on other parts of the members, excepting 

 that it is somewhat smoother. 



III.— Breeding. 



1. Mating and Fertilization. — Gage ('91) states 

 that an autumnal mating, at any rate so far as the 

 male's part in the process is concerned, takes place in 

 D. viridescens. Spermatophores, he says, are emitted 

 precisely as in spring, or the proper breeding season. 

 Copulating pairs of D. torosus are not infrequently seen 

 in the early fall in the streams and ponds of this local- 

 ity. Thus last year I observed such a pair as early as Sep- 

 tember 23d. Instead, however, of there being an autumnal 

 as distinct from a spring mating in this species, we have to 

 say that the season's amours begin thus early in the year, 

 for the process goes on without interruption from its begin- 

 ning to the termination of the breeding time. But here as 

 in D. viridescens it is an affair of the males alone. Sperm 

 masses are discharged but there are no ova for them to fer- 

 tilize till some months later, as we shall see further on. 

 Gage is at a loss to understand the significance of the au- 

 tumnal mating in D. viridescens. From what has been said 



