THE GENESIS OF THE EGG IN TRITON. 261 



mens have been obtained. The average length of the adult 

 male is 9-5 cm., female 11*7 cm. 



Tlie females are generally larger as well as longer than 

 the males. The only external sexual differences, aside from 

 size, are found in the form and length of the tail, and in the 

 size and form of the cloacal lips. In the male the tail is 

 short and broad with an obtuse apex, while in the female it 

 is elongated ;and narrow, and somewhat pointed at the 

 extremity. The cloacal orifice of the female is an elongated 

 slit, the lips of which have a swollen appearance. In the 

 male the lips are much larger and the slit much longer, the 

 whole being well adapted for clasping the cloacal slit of the 

 female in the act of copulation. 



For keeping specimens I have been obliged to make use 

 of small glass aquaria, the water being kept in a tolerably 

 good condition by such water plants as Chara and 

 Vallisneria. 



Their food consists of worms, insects' larvae, small mol- 

 luscs, &c. They will eat pieces of fish, and even grains of 

 boiled rice. When they are extremely hungry they some- 

 times bite one another. I observed one instance in which 

 a poor small fellow was swallowed up to the middle part 

 of the body by a larger and stronger one ; but the latter 

 had undertaken too much, for he was unable to complete 

 tlie act of swallowing or to disgorge, and finally died, after 

 vain attempts to free himself from the obstinate morsel. I 

 have also observed that among young specimens reared in 

 an aquarium the larger ones sometimes devour the smaller 

 and weaker ones. 



Although I have never seen the act of copulation, I think 

 there can be no doubt that such an act takes place, as I have 

 often found spermatozoa in the oviducts.^ The manner in 

 which fecundation takes place was made known in 1864 by 

 Professor Nauck, in the ' Correspondenzblatt des Naturfor- 

 scher-Vereins zu Riga.' This paper is known to me only 

 through an article by Dr. J. V. Bedriaga in the ' Zoologischer 

 Auzeiger,' No. T9, 1881, p. 157. As here quoted, Professor 

 Nauck's statements run thus : 



'• Prof. Dr. Nauck (heisstes auf p. 85 des correspondenz 

 blattes zu Riga), berichtete die von ihm einmal beobachtete 

 Begattung zweier Tritonen. Nachdem bei dem sonst Kamm- 

 losen Mannchen sich ein Kamm iiber Rucken und 



' Professor Gasco's recent observations (' Zool. Anz.,' Nos. 85 and 8G) 

 on Triton and Axolotl sliow that no real copulation takes place in these 

 Urodela, since the spermatic fluid is not conveyed to the female by cloacal 

 contact. 



