EXTINCT SCALED REPTILES. 
249 
without provocation, leaping towards him from a considerable distance when he 
approaches. I met, in the course of my daily rambles through the woods, many 
jararacas, and once or twice very narrowly escaped treading on them, but never 
saw them attempt to spring. On some subjects the testimony of the natives of a 
wild country is utterly worthless. The bite of the jararacas is generally fatal.” 
Extinct Groups of Scaled Reptiles. 
A brief reference may be made to two groups of extinct reptiles from the 
rocks of the Secondary epoch, which must be included in the order Squamata. 
Long-Necked The first of these groups is represented by a small snake-lizard, from 
Lizards. the English Chalk, described under the name of Dolichosaurus, and 
forming a suborder (Dolichosauria) by itself. Whereas ordinary lizards have not 
more than nine vertebrae in the neck, this strange reptile has upwards of from 
fifteen to seventeen, while its hind-limbs are characterised by having the whole of 
the five metatarsal bones of the foot well developed, and its whole structure 
reveals a very generalised type of organisation. The vertebrae have additional 
articulations like those of snakes. It is probable that these reptiles form the 
ancestral group from which the other suborders of scaled reptiles have originated. 
Cretaceous A still more remarkable group of the order is formed by certain 
Sea-Serpents, carnivorous marine reptiles from the Cretaceous rocks, many of which 
attained gigantic dimensions, and may not inappropriately be designated extinct 
sea-serpents. Commonly known as Mosasauroids, on account of the first described 
genus ( Mosasaurus ), having been found on the banks of the Meuse, they form a 
suborder technically known as the Pythonomorpha, They all had a much elon¬ 
gated body, and a skull approximating in structure to that of the monitors among 
existing lizards, the nasal and premaxillary bones being welded together, and the 
quadrate very loosely attached to the skull. Teeth were present on some of the 
bones of the palate, as well as on the margin of the jaws; those of the latter series 
being large, sharply pointed, and attached by expanded bases. The bones of the 
shoulder-girdle and pelvis were more or less imperfectly developed; and the limbs 
were modified into paddles or flippers, with the toes enclosed in a common skin, 
and devoid of claws. There were either nine or ten vertebrae in the neck; and 
whereas, in some cases, the vertebrae resembled those of snakes, in other instances 
they lacked the additional articulations distinguishing the latter. It will be un¬ 
necessary to particularise the various genera of these reptiles, but it may be 
mentioned that while some of the better-known forms have been described as 
Mosasaurus , others have received the names of Liodon and Clidastes. They appear 
to have inhabited the Cretaceous seas of all parts of the world, having been 
obtained from regions as far apart as England, New Zealand, and Argentina; and 
while some attained a length of between 25 and 30 feet, others were not more 
than 8 or 10. Then, again, while in some cases the jaws were armed with power¬ 
ful teeth to their extremities, other forms had a long, toothless beak. 
