i64 WATER REPTILES OF THE PAST AND PRESENT 



oviparous, as are most other lizards. But this, after all, may be 

 a hasty inference. 



No known reptiles lay their eggs in the water. Perhaps there 

 is some reason why the eggs of reptiles and birds, so different from 

 those of fishes and amphibians, cannot hatch in water; and there 

 is no good reason for supposing that the mosasaurs were exceptions 

 to this rule. Unless carefully hidden or protected by the parent, 

 the eggs or very young of the mosasaurs would have been subject 

 to many and grave dangers. Fish eggs are usually small and pro- 

 duced in great numbers, thousands often being extruded from a 

 single female. Among so many there is a greater probabiUty that 

 at least two will hatch and survive to maturity, reproducing their 

 kind. It is unreasonable to suppose that the lizards of the past 

 were more prolific of eggs than are their relatives now living; nor 

 is it possible that their eggs could have been as small as are those 

 of most fishes. Modern lizards seldom lay more than twenty-five 

 or thirty eggs at a time; even the turtles, with their greater vicis- 

 situdes, seldom produce more than one hundred. The eggs of 

 the mosasaurs were certainly large and few in number, and the 

 young animals must have begun breathing air immediately after 

 escaping from the shells. If the mosasaurs were oviparous they 

 must have laid their eggs upon the shores and beaches, as do the 

 sea-turtles and the Crocodilia. Nor is it at all probable that the 

 female mosasaurs gave even that protection to their eggs or 

 young that the crocodiles and turtles give. The young mosasaurs, 

 perhaps reaching a foot in length, must have been left entirely 

 to their own devices and their own fate at the very earliest stages 

 of their independent careers. 



The waters in which the mosasaurs abounded swarmed with 

 many kinds of predaceous fishes, to say nothing of the hordes of 

 their own kinds, all carnivorous in the highest degree, to all of 

 which the tender saurians must have been choice food. Possibly 

 the shallow waters of the bays and estuaries may have afforded 

 protection to the newly hatched reptiles. It would seem probable 

 that the female mosasaurs went up the rivers for a shorter or longer 

 distance to lay their eggs or give birth to their young, and that the 

 young reptiles remained in such relatively protected places until 



