In serpents the eggs differ from those of birds by undergoing a sort of incubation from the very first, so that whenever examined, the embryo more or less advanced will be found. In the case of the pythoness of 1862, an egg was examined on the fifteenth day of incubation, and found to contain a living embryo; a noteworthy fact, as the python incubates for fifty-six days before hatching her eggs. Observations with the eggs of chilobothrus are attended by the same results—namely the fetus in a certain stage of development is discovered whenever a gravid snake is killed and examined. The young ones of the boa in the London collection were perfectly developed and active, climbing all over their cage as soon as they saw daylight. One family consisted of thirty-three; another of eight; and another of fourteen. The activity and daring of the snakelings were amazing, affording ample proof of their perfect development. They were always on the defensive, shewing fight on the slightest molestation. When the keeper put his hand into the nest among them they seized upon it and held on so tightly with their teeth, that on raising his hand they hung to it, wriggling and undulating like a waving golden tassel. I ventured to take up one of these aggressive little reptiles, but could scarcely hold it, from its energetic wrigglings and contortions. It constricted my fingers tightly enough to prove its singular instincts, and bit me savagely with its sharp little teeth; but my glove being on, I permitted this, glad of so good an opportunity for making personal observations.
It was said of the python that notwithstanding her care and vigilance so long as she was incubating, when her snakelings were born she took no notice of them. This may not always be the case. Vipers we know are extremely watchful over their young; other snakes are often seen accompanied by a young brood; and in the Jamaica boa maternal affection is exhibited in no slight degree. A lady visiting the Gardens compassionated one of these young families on the gravelly floor of their cage, and brought a quantity of cotton wool, which was placed in one corner. She was rewarded by seeing the luxury fully appreciated, mother and little ones all huddling into it immediately.
That these non-venomous snakes thus produce their young under abnormal conditions is further confirmed by the varying size and appearance of the offspring, and by their being more or less enveloped in the shell-covering. Some are born quite coiled in the ruptured shell, others with portions of it clinging about them, and others again entirely free. Sometimes they are, as it were, imbedded in the coriaceous covering. This was conspicuously the case with the anaconda's progeny, but her young ones had every appearance of having been a long while dead. The first of the six was freer from the shell than the others, and about a foot and a half in length.
Snake-life is altogether marvellous. The power which some snake mothers possess of retarding the deposition of their eggs, and we have reason to believe, sometimes even the young when circumstances are unpropitious for her to produce them, seems to us specially curious. Chilobothrus is known to have had both eggs and a living brood. So has Coronella lævis. Of the latter, some German ophiologists state that it is 'always viviparous;' others 'occasionally' so. In her native Hampshire woods she has been seen with a young brood about her; but there seems no satisfactory evidence of any eggs having been found. Time and careful notings only can substantiate this and many other singular facts regarding these 'wise' and 'subtle' creatures, hitherto surrounded by prejudice and but little studied. We, not well versed in Ophidian biographies, might have expected the anaconda to lay eggs because her cousin the pythoness did so; and we might have also speculated upon her incubating them, as the python did. But she has produced a perfectly developed though dead family of six, instead; a circumstance of so much interest to naturalists, that the loss of the young ones is to be regretted though not wondered at. Captured from her native lagoons, and shut out from the light of day in a box just large enough to contain her, this 'good swimmer' arrives alive; thus proving her amazing powers of endurance; but she has had no fitting place in which to deposit her young, and they died unborn. Still it is a noteworthy fact in the annals of zoology. At first, from the result of observation, the incubation of the python was 'suspected;' then it became confirmed; and the birth of young coronellas also. From this it is evident that we cease to declare that only vipers produce live young; or, according to the original signification of the word, a boa, a coronella, and several other non-venomous snakes would be 'vipers!'
Again, it is remarkable that these peculiarities of reproduction are not confined to particular families and genera; because some coronellas lay eggs, some incubate them, and others bring forth a live brood. So also, while some of the Boaidæ lay eggs, the anaconda is completely viviparous.
We would venture to urge upon those lovers of nature who dwell 'remote from towns' the value of careful observation and a noting down of what appears unusual, even of the habits of the much persecuted snake.
C. H.
[PLAYTIME AT OXFORD.]
'What is to be done this afternoon?' is a question invariably asked by scores of undergraduates, either at the well-supplied breakfast-table (for whatever men do not learn at Oxford, they at least learn to eat a good breakfast), or by those victims of procrastination who leave everything to the last moment, just as the scout is bringing up the more modest luncheon.