The Nattek-jack.- 



-KEPTILES.- 



-Tkee-frogs. 



93 



tlie fore ones, and finally the wbole is detached, 

 ]nished by the two hands into the mo'.'th in a little 

 ball, and then swallowed at a single gnlp ! 



THE NATTER-JACK [Dufo calamita) is another 

 European species, and is found, equally with the com- 

 mon toad, in various parts of Great Britain. It is, 

 however, much more local than the other, and appears 

 confined to certain districts. It is said to be truly 

 indigenous to Ireland, the only instance of an indi- 

 genous native reptile in that country. It is not quite 

 so large as the common toad, the body being only 

 about two and three quarter inches in length. It is of 

 a light yellowish-brown colour, clouded with duU olive, 

 a bright yellow line running along the middle of the 

 back. The Natter-j.ack is not so " heavy-gaited" as 

 the common toad, for when it is excited it runs toler- 

 ably quick, its body being raised considerably above 

 the ground duiing its progress. It is far more capable 

 of sustaining drought than the other species, and is 

 often observed to climb on walls and trees, and con- 

 ceal itself in holes. Professor Bell says (hat this 

 animal is very common in bis garden at Selborne, 

 and that he has often found several of them lying 

 under the shallow laj'er of turf covering the top of a 

 wall of a ha-ha there, exposed to the powerful rays of 

 the smiimer's sun, in the hottest and dryest situation 

 in the garden. It is common in France, and in Saxony 

 it is frequently found in the houses. It never goes to 

 the water but for the purpose of reproduction ; the 

 union of the two sexes taking place in spring, in the 

 water, and the metamorphosis of the young undergoing 

 the same stages as the common toad. The skin of 

 the Natter-jack is said to exhale a strong odour of gun- 

 powder. 



America produces a number of toads, and of various 

 sizes, but we hasten on to the curious " Tree-frogs." 



TREE-FROGS {Hylina). 



The second series of Batrachians with the tongue 

 adherent in front {OpisthoQlossa), is composed of 

 species which have the fingers and toes dilated into 

 discs at the extremities — fig. 26. These form the 



Fig. 26. 



n yla— fore ftet and dilated toes of two species. 



Droad-tced Opisthoglossa {Opisthoglossa plutyclactyla), 

 and are synonymous with what are well known as Tree- 

 frogs. The species are numerous, and by far the greater 

 number belong to tlie section IfyUna, which is charac- 



terized by the animals belonging to it having maxillary 

 teeth and a well and perfectly developed ear. Tree- 

 frogs form a very natural group of Batrachians, and 

 the distinguishing character of the fingers and toes being 

 dilated into discs covered with a viscous secretion, is 

 most important, and influences their whole mode of 

 existence. By means of this organization these crea- 

 tures can adhere to smooth surfaces, as glass, leaves of 

 plants, &c. ; and they are thus enabled to climb trees, 

 to leap from branch to branch, and to traverse with 

 facility the moving leaves of plants, shrubs, and trees 

 agitated by the wind. Tbeu' actions are more like 

 those of a bird than a reptile, and their great agility 

 and extraordinary suppleness render them able to 

 make their way with great dexterity on the most 

 flexible branches. The mode, however, in which 

 these animals are qualified for their arboreal habits 

 yet remains to be explained. " The monkey," as Jlr. 

 Martin remarks, " grasps with his paws the perch on 

 which he rests ; the bird with its claws ; the snake 

 entwines itself around the branch ; the iguana uses 

 its long toes and hooked nails ; the chameleon holds 

 tlie bough tight between its vice-like toes ; but the 

 foot of the Tree-frog acts dilferently fi-om the foot ot 

 these animals. It is not a grasping organ, nor is it 

 furnished with claws for clinging ; but it is provided 

 with suckers, analogous to those we have noticed in 

 the foot of the gecko. On the under surface of each 

 finger (both of the fore and hind paws) at the tip, 

 which is enlarged and rounded, is placed a sucker, 

 consisting of a little cushion, moist with a thick glutinous 

 fluid, and applying itself so closely to the surface it 

 touches as to support the creature's weight. This 

 mechanism is, however, under the animal's c(mtrol, 

 as it can disengage or fix its fingers at will." The 

 Tree-frogs feed upon all kinds of insects, small worms, 

 &c, and during the fine weather of summer they pur- 

 sue their prey amongst the leaves of the trees, on which 

 they then reside, with astonishing agility. Later in the 

 season, however, they retire to the bottom of ponds, 

 and, like frogs, pass the winter there in a state of tor- 

 pidity. The union of the sexes takes place also in the 

 water, the spawn is deposited there, and the develop- 

 ment of the eggs and young take place in the same 

 manner as in the frogs and toads. They are noc- 

 tiunal in their habits. In the day-time, and particu- 

 larly when the heat of the sun is greatest, they shelter 

 themselves in shady places, where the trees afford a 

 thick foliage ; but when twilight begins they put them- 

 selves in motion, and enjoy their sports and gambols 

 in security. The males are proM'ded with large vocal 

 sacs, and the croaking noise which they prod\ice is 

 stronger even than in the Edible frog itself During 

 or previous to rain, and in the middle of the fine nights 

 in summer, the Tree-frogs may often be seen assem- 

 bled in numbers on the tops of trees, sending forth in 

 chorus their hoarse and discordant music. Besides 

 the dilated tips of the fingers and toes possessed by 

 these animals, they have another character vdn'ch dis- 

 tinguishes them from the tribes already noticed. This 

 is the existence of numerous small granulations with 

 glandular openings on the inferior surface of their 

 belly. Their hind legs also are very long. 



