EEPTILES. 161 



same coinradesliip still kept up on tlie distant coasts of 

 Australia. 



Quite recently anotlier link connecting tlie present 

 fauna of Australia witli tliat of Secondary Europe has been 

 discovered. For a considerable time a jjeculiar group of 

 herrings (Diplomysius), characterized by having a row of 

 scutes on the back resembling those found in other types 

 on the opposite aspect of the body, have been known from 

 Cretaceous and early Tertiary rocks, their range including 

 Brazil, 'Wyoming, the Isle of Wight, and the Lebanon. 

 Till the other day, these doubly-armoured herrings were 

 considered to be totally extinct, but now, lo and behold ! 

 thev have turned up alive in certain rivers of ISTew South 

 Wales. 



Among amphibians, the creature which seems best 

 entitled to be called a "living fossil" is the giant 

 salamander (Cryptobranchus) of Japan, since, together 

 with a smaller North American kind, it is the representa- 

 tive of a genus once common in Europe during the middle 

 portion of the Tertiary ^jeriod. Indeed, our first know- 

 ledge of the group was derived from a fossil specimen of 

 one of these salamanders from the continent, described in 

 the year 1726 under the title of homo diluvii testis, in the 

 belief that it was a human skeleton ! 



Passing on to the reptilian class, we have to notice that 

 in the year 1842 Sir E. Owen described from the Triassic 

 rocks of Shropshire the remains of a small lizard-like 

 reptile (Rhyiichosaurus), differing from all living forms in 

 the structure of its skull, of which the jaws terminated 

 in a peculiar beak. Eleven years previously Dr. Gray 

 had, however, apjjlied the name SpTienodon to a then very 

 imperfectly known living reptile from New Zealand ; 

 which when fully described by Dr. Gunther in 1867 

 turned out to be very closely related to the Triassic 

 RhynchosciMrus. Although externally somewhat like a 

 lizard, but with a different kind of skin, the tuatera, as 

 the Now Zealand reptile is called, differs entirely in the 

 structure of its skull and skeleton in general from the 

 true lizards, and comes much closer in these respects to 

 crocodiles and tortoises. Subsequent researches have 



