LECTURES ON EMBRYOLOGY. 



in that class in which we have the most matured 

 materials for such an investigation. I might have 

 selected a more worthy subject than frogs and 

 salamanders, and perhaps have alluded to the 

 higher animals. But let me say, there is nothing 

 unworthy of our attention in nature. And if we 

 can trace the action of the creative power in these 

 animals which we despise, let us consider that 

 they were made by Him, and if they were worth 

 making, they are worth considering by us. 



The class of reptiles as it is now circumscribed, 

 is a very natural one, though it was not always so 

 in the works of natural history. There was a time 

 when crocodiles, lizards, turtles, were not ranked 

 among reptiles, but were placed among quadru- 

 peds, with all the higher animals all the higher 

 mammalia and when reptiles were to naturalists 

 only serpents and frogs ; and even then they divi- 

 ded those animals into two groups the creeping 

 snakes in one, and the jumping batrachia in the 

 other. 



Laurenti, an Austrian naturalist, was the first 

 who described these most carefully, bringing to- 

 gether frogs, lizards, turtle, salamanders, toads, 

 and combining in one natural division all the 

 principal animals which we now refer to it. 

 But his classification was not much better on that 

 account. He placed in one and the same division, 

 salamanders, and lizards, and crocodiles, which we 

 now know to be widely different ; and he did not 

 place in that class another group of animals, which 

 we refer to it the Csecilia. I shall not enter into 

 too many details, for fear I should not finish what 

 I have to say this evening. 

 Linnaeus followed the same example. He brought 

 together turtles, crocodiles, lizards, snakes, frogs 

 and salamanders, but unfortunately left in the 

 same class some fishes, which he combined with 

 the reptiles, owing to some peculiarities of their 

 solid frame. Linnaeus also left the salamanders 

 with the lizards, because they had four legs. 



Here is one of these animals [Plate IV, fig. F ] 

 Brongniart, the celebrated geologist of Paris, stud- 

 ied these animals, and happily threw great light 

 upon the subject, when he showed that reptiles 

 could be divided into four groups the turtles 

 being one, the lizards another, the snakes a third 

 and the Batrachians, as he called the frogs and 

 salamanders, the fourth and last group. And in 

 this, for the first time, we see salamanders sep- 

 arated from lizards and brought into connexion 

 with frogs and toads. He had noticed that these 

 animals undergo similar changes that they are 

 equally naked that they have not the scales 

 which characterize higher reptiles, and he there- 

 fore brought them together, but he : left out an 

 animal which really belonged to that class. A 

 naked snake called Cascilia by naturalists, was left 

 out and included among the snakes. 



I shall use the term Batrachia to designate all 

 those animals which are allied to frogs and sala- 

 manders. We have a great variety of these ani- 



[PLATE IV SALAMANDERS ] 





mals. After the publication of the works of Brong- 

 niart, Oppel, Dumeril. etc., (who also introduced 

 new views on the subject) they were extensively 

 studied, so that in the museums these animals be- 

 came more numerous, and it became necessary to 

 introduce some subdivisions among them. Xow 

 let me show what sort of animals are referred to 

 this order of Batrachia. And in the first place we 

 have the type of frogs. [Plate III ] Animals 

 which have four fingers in the anterior leg, and 

 five behind. There is no tail to those belonging 

 to this group we refer to the frog and the 

 treetoad. There is a web in the finger of the frog; 

 but in the tree toad there is a kind of web, and it 

 is floating. But in the toad the fingers are entirely 

 free. 



In the salamanders there is a tail. There }ave 

 four fingers at the termination of the anterior ex- 

 tremity and five at the termination of the posterior 

 extremity. Without the tails, salamanders would 

 be compared with frogs and toads. If their body 

 was somewhat more contracted they would resem- 

 ble each other very strongly. And indeed, their in 

 ternal structure is similar. On account of the 



