350 THE ZOOLOGIST. 



presence. And for every one of the few cases which have heen 

 noted in captivity there have heen fifty where no attempt at 

 incubation has been made. 



Nevertheless some very extraordinary anomalies have been 

 pointed out with regard to these creatures in this respect. It 

 appears that if a serpent, normally at the full period of ovo- 

 gestation, finds no suitable place for its purpose, it has the power 

 of retaining the eggs for a considerable time, so that they may be 

 hatched within the body of an individual whose species is not 

 ovo-viviparous (this would probably be accompanied by an 

 exacerbation of temperature) ; and it is even said that the 

 released brood may be retained within the uterus, or oviduct, 

 until the external conditions are favourable for their extrusion. 

 I believe the subject was first brought forward by Mr. P. H. Gosse, 

 in some observations on Chilobothrus inoniatus, made in Jamaica. 

 It has not yet been thoroughly investigated, and will indeed be 

 very difficult to pursue, since to be of much value it must be 

 followed out among snakes in their wild state. Any embarrassment 

 in this particular with specimens in confinement generally results 

 in abortion or arrest of nutrition, or death of the prospective 

 parent. In the case of a boa-constrictor (pythoness, Python seba? 

 it was captured on the St. Paul River, Monrovia, Liberia, West 

 Africa) which died suddenly at the Clifton Zoological Gardens in 

 May, 1857, having been " in great health and beauty to within an 

 hour of its death," and which was carefully dissected by Mr. Frank 

 Buckland and other medical men prior to the maceration of its 

 skeleton for the museum of the Royal College of Surgeons, no 

 symptom of disease was discovered, and the cause of death could 

 only be conjectured to be the want of a sufficient depth of sand 

 in its den wherein to deposit the forty large mature ova which 

 were found in it. On the other hand, ovo-viviparous snakes will 

 occasionally extrude their eggs unhatched, from fright, injury, or 

 other causes, and the living young may emerge subsequently. 

 Thus, though different species are tolerably constant in their 

 habit, it seems as though no very distinct line of demarcation 

 can be drawn between oviparse and ovo-viviparse, so far as the 

 actual process is concerned ; and this close affinity is borne out 

 by the fact that the eggs of some species, recognised as oviparous, 

 are hatched almost immediately after their deposition, while 

 others require a great length of time for their maturation. Those 



