440 AMPHIBIA— ORDER I.—ECAUDATA. 



ties of the transverse processes of the sacral vertebra. It is an ugly- 

 looking creature at best, the large triangular head bearing ridges, and 

 the pointed nose being surmounted with a loose flap of skin, and similar 

 flaps covering the eyes. The mouth, too, is of enormous capacity, and thus 

 adds to the "generally repulsive appearance of this frog. The sharp-nosed 

 frog is evidently a highly specialised species, since it lays very large eggs, 

 from which young frogs emerge in a highly developed condition, the tadpole 

 stage being compressed and passed in the eggs. Mr. Guppy writes that 

 " during the descent from one of the peaks of i'aroe Island, I stopped at a 

 stream some 400 feet above the sea, where my native boys collected from the 

 moist crevices of the rocks close to the water a number of transparent, 

 gelatinous balls, rather smaller than a marble. Eacli of these balls contamed 

 a young frog about a third of an inch in length. On my rupturmg the ball, 

 the tiny frog took a marvellous leap into existence, and disappeared before I 

 could catch it." 



Sub-Order II. — Arcifera. 



The remaining families of the order in which the tongue is present con- 

 stitute a second subordinal group, differing from the first by the conforma- 

 tion of tlie bones and cartilages of the chest. Instead of the two metacora- 

 coid bones being connected together in the middle line by a single cartilage 

 attached to their free inner edges, each of the metacoracoids is expanded on 

 the same side into a plate of cartilage, one of which overlaps the other. 



Having the above-mentioned type of chest-structure, the large and important 

 family of the Leptodactylidce. — the Cystignathidce of many authors — are spread 

 over Central and South America and Australia. In all of 

 Family them only the upper jaw is furnished with teeth, and the 



Leptodactylidoi. extremities of the horizontal transverse processes of the 

 sacral vertebra are either cylindrical, or only slightly ex- 

 panded. In both these respects these frogs resemble the Banidce, so that they 

 may be regarded as holding the same relative position in the present sub-order 

 as is occupied by the latter in the Firmisternia. More than a score of genera 

 and a very large number of species are included in the family, and it may be 

 noted that whereas in the majority of the Australian genera the pupil of the 

 eye is vertical, this is but seldom the case in the American forms. The family 

 may be divided into three groups, in the first of which the breast-bone ter- 

 minates below in a rod-like process. To this group belongs the typical genus 

 Leptodactylus, of which all the numerous species are American. These frogs, 

 in which the pupil is horizontal, are much like the Ranidce in external 

 appearance, but the hind-toes are not webbed. They are peculiar in that 

 during the breeding season the fore-limb becomes much swollen, and in 

 the skeleton the humerus bears a conspicuous bony ridge. All these frogs 

 possess a very powerful voice, and in parts of the Argentine their croaking is 

 a dreadful nuisance. Many of them burrow holes in the ground for their 

 eggs. As an example of the second group, in which there is no bony rod to 

 the breast-bone, and the hind-toes are nearly or completely free, we may take 

 a West Indian species (Hylodes martinicensh) belonging to a large American 

 genus, all the species of which are arboreal. This particular kind has the 

 peculiar habit of laying its large eggs singly in the axils of leaves, where a few 

 drops of water may from time to time collect after a shower. From these 

 eggs the young frogs emerge with only a small remnant of the tail, which is 



