372 Mr. J. Higginbottom on the British Tritons. 



the ova are the Veronica anagallis, and the long grasses which 

 abound in some pools. 



The Veronica anagallis has a firmer leaf than the Nasturtium 

 aquaticum, is formed into fii'mer folds, and is thus better cal- 

 culated for enclosing and protecting the ova. The long grasses 

 appear still more favourable for this purpose, and are best suited 

 for the security of the ova ; they admit of four or five or more of 

 the ova being deposited singly in folds on a single blade. Each 

 ovum is generally placed in the centre of that part of the blade 

 on which it is laid, and is neatly covered within a fold in such 

 various directions as frequently to present a fantastic appearance, 

 when the whole or the greatest part of the blade is folded. 

 Almost any aquatic plant serves as a receptacle of the ova. I 

 have seen them deposited even within the linear leaves of the 

 Ranunculus aquaticus, so compressed as to secure the ova. 



The Triton, when depositing its ovum, first rests with the 

 lower part of the body across a leaf or blade of grass ; this it 

 folds up by means of its posterior extremities, making repeated 

 acts of pressure with them until the fold is sufficiently complete 

 to admit of the secure insertion of the ovum ; when that is ac- 

 complished the posterior extremities are pressed together upon 

 the enclosed ovum for a minute or more, when the little animal 

 quits it to deposit another ovum. The ovum when first de- 

 posited is round and has a small white yolk in its centre, which 

 has no attachment within its envelope, but is surrounded by an 

 aqueous fluid, within a firm transparent capsule. 



A soft jelly-like substance covers the surface of this capsule, 

 which materially assists by its adhesive property in securing the 

 ovum and preserving it from too great exposiu-e to the water, an 

 event which at an early period often destroys its vitality, in which 

 case it is seen to become covered with mould. In about a fort- 

 night the ovum becomes so large as in some degree to sever itself 

 fi'om the fold of the leaf, and some parts of the ovum now come 

 freely in contact with the water without injury ; indeed, the free 

 exposure to the water appears necessary for its further develop- 

 ment. By the experiment of putting some ova into water coloured 

 with saff'ron for a short time, it will be found that they exhibit 

 an appearance of little golden balls, and by removing them after- 

 ward into clear water for a time, they become colourless, proving 

 that there is a constant endosmose and exosmose through each 

 ovum, so that there is a constant- supply of fresh water for the 

 presei'vation and further development of the embryo. 



The safety of the ovum depends also, at an early period of its 

 development, upon the integrity of the leaf on which it is depo- 

 sited, as I have already stated, for when this is much broken in 

 folding, when the plant is too delicate of fibre, or from other 



