No. 486] HABITS OF AMBLYSTOMA 



On account of the late season at which my investigation was 

 begun, no direct observations of the process of fertilization were 

 possible. Clark (79) says of some specimens of A. pundatum 

 m conhneinent: "The males showed no inclination to clasp the 

 females, but (juietly deposited quite large masses of an apparently 

 rather thick liquid, opaque white, on the bottom of the dish in 

 which they were kept. Upon examination this was found to con- 

 sist of spermatozoa moving actively in a licjuid." The manner in 

 which the spermatozoa reached the eggs was not observed. 



Fertilization is undoubtedly internal. Of this the evidence 

 adduced by Kingsbury ('95), and the presence of spermatozoa 

 in the cloaca of the female as described above, furnish sufficient 

 proof. It remains to consider how the transfer of spermatozoa 

 is effected by the spermatophores. 



The number of spermatophores is evidently very much greater 

 than the number of females; and unless there exists an enormous 

 disproportion between the sexes, each male must deposit a large 

 number of spermatophores. Their abundance and the manner 

 of their distribution, render it a very easy matter for the female 

 to find enough of them for purposes of fertilization. In some 

 portions of the pond it would seem scarcely possible for a female 

 to move about in the water for any length of time \\ itiiout l)rnshing 

 against some of these spermatophores; hence tlu>re is the possi- 

 bility of finding them bv chance contact. 



In the ca^-s nf thos,-' rrodela in whic-h, as in Triton r/r/./r.™ 

 (Jonlan -HI and Ilihon an.l Ax.)lotl ((iasco M) the 



number of spermatophores <lep.)sited In- a single male is small, 

 particular safeguards are needed in order to facilitate their delivery 

 to the cloaca of the female. In tlies(> forms the physiological 

 necessity which re(|uires the co-operation of the female in order 

 that spermatophores mav be deposited insures the presence of the 

 female at the right time; su!.st>(|nent reactions safeguard the 



the spermatophore. The complicated behavior of the adults in 

 these cases finds its biological significance not only in the increasing 

 certainty of the process, but in a corresponding economy in the 



