2IO 



BERTRAM G. SMITH. 



single, in one case the male was observed to return repeatedly, 

 at intervals of several minutes, to the same spermatophore and 

 deposit another on top of it, thus building up a compound sper- 

 matophore consisting of seven simple spermatophores. Whether 

 the compound spermatophore of Amhy stoma punctatum is built 

 up in this way I have no means of dedding ; it would seem quite 

 as probable that the spermatophores were deposited in rapid 

 succession, while the animal remained in one place — a condition 

 not far removed from what occurs in external fertilization, in 

 which a large amount of seminal fluid is discharged at once. 

 In any case it is difficult to see that any advantage is gained by 

 depositing one spermatophore on top of another and thereby 

 destroying the efficiency of the one previously deposited. As 

 already noted in the case of Amhy stoma punctatum, the spermato- 

 zoa of these spermatophores retain their vitality in water for 

 many hours. The formation of compound spermatophores of 

 the vertical-serial type seems to me a useless and wasteful pro- 

 cedure, and the large proportion of such spermatophores indicates 

 that the spermatophore-forming habit is not highly evolved nor 

 perfectly adapted to its purpose. 



In my previous paper (Smith, '07) on the breeding habits of 

 Ambystoma punctatum, I ventured the prediction, based on the 

 large number of spermatophores and the manner of their distri- 

 bution, that the behavior of the adults in the fertilization process 

 would be found to be simpler than in the case of Diemyctylus 

 viridescens. In the latter case only a very few spermatophores 

 are formed by each male, and particular safeguards are necessary 

 in order to insure the delivery of at least one of them to the fe- 

 male cloaca; these safeguards are furnished by the complicated 

 but definite series of acts on the part of the adults which precedes 

 and conditions the deposition of a spermatophore. Just as in 

 the higher vertebrates economy of egg production is correlated 

 with care of the young, so in Diemyctylus economy in the pro- 

 duction of spermatophores is accompanied by a considerable 

 amount of certainty as to their fate. This prediction as to the 

 relative simplicity of the behavior of the adults of Ambystoma 

 punctatum, the recent observations of Wright and Allen ('09) 

 have abundantly justified. In the light of the observations on 



