BATEACHIA. 399 



eating influence of a dry atmosphere, falling into a state of lethargy identical with the winter- 

 sleep of the species inhabiting colder climates. Their lungs consist of two capacious sacs, 

 which may be so much expanded that the animal assumes nearly twice its natural volume. 

 When they dive the lungs are emptied, and the respiration remains interrupted for one or 

 two hours, after which time the animal is compelled to rise to the surface in order to breathe. 

 However, the necessity of breathing depends entirely on the energy of the other functions, 

 as during hibernation or during the lethargy in the dry season the respiration is suspended 

 for months*. Many Batrachians are endowed with a powerful voice, being provided with 

 one or two membranaceous gular sacs. In the species which have two, one is situated at 

 each side of the lower jaw, whilst in those having a single one it is placed between the 

 branches of the mandible. In either case the vocal sac opens by two slits in the cavity of the 

 mouth, and is filled with air from the lungs. These vocal sacs are peculiar to the male sex. 



The skin is sometimes smooth, sometimes tubercular and glandular, the glands being 

 either equally distributed over the whole surface of the animal, or aggregate. Such an 

 aggregate gland is very frequently found above the tympanum, on each side of the neck, and 

 having been compared with the parotid of the mammals, it has been termed 2Mrotoidj' ; it is 

 merely a cuticular gland, and as it does not discharge its secretion into the cavity of the 

 mouth, it has no reference whatever to the alimentary functions. 



We have mentioned above that many Batrachians live at some distance from water ; all, 

 however, as far as is known at present, enter it at the season of propagation. The copulation 

 is prolonged over several days, during which time the male holds the female tightly clasped 

 with its fore legs. The males of many species may be externally distinguished by a rough 

 swelling of their thumbs, or — as is the case in some American and Australian species — by 

 short conical spurs on the thumb or in the sternal region. The males have also generally a 

 distinctly more slender form than the females. The eggs are impregnated the moment they 

 are deposited by the female in the water; during their passage through the oviduct they 

 are surrounded with a gelatinous coat, which swells in the water and protects them from 

 changes of temperature. The young ones, or Tadpoles, have a thick ovate body without 

 legs, terminating in a long, strong, compressed tail, which serves as an organ of locomotion 

 in the water. They are true aquatic animals, breathing by gills (which are enclosed in a 

 cavity in the Tailless Batrachians), and having the same anatomical and physiological arrange- 

 ment of the organs of circulation as fishes. The mouth is very narrow, and the jaws are 

 armed \vith a hard, horny covering. Theii' food consists chiefly of living or decaying vegetables, 

 but also of decomposing animal substances ; and in accordance with this kind of food, so 

 difierent from that taken by them after their metamorphosis, the intestinal canal is spirally 

 contorted and much longer than in the perfect animal. In proportion as the gills are super- 



* The suspension of the vital functions of the Batrachians, and their tenacity of life, has given rise to 

 some fabulous tales. It has been iiroved that some of them wiU survive a lethargic state continued for 

 years ; but every attempt to rev-ive the old stories of toads enclosed in coal-beds or rocks testifies to a 

 lamentable ignorance of the merest elements of geology and physiology on the part of those wlio put 

 forward such statements. 



t I prefer this term to that of parotid, as the gland of the Batrachians is very diiferent from the parotid 

 of the higher classes of animals ; it is compounded of 7rapwTi<; and elSo:;, and has unfortunately been misspelt 

 paratoid in the ' Catalogue of the Batrachia Salientia.' 



