iS95. MORPHOLOGY AT THE NATIONAL MUSEUM. 267 



part is free and can be rapidly protruded from the mouth. In Pipa 

 and Xcnopus however the tongue is wanting. In some Anura 

 {e.g., Discoglossidce) and in the salamanders the tongue is not 

 protrusile, and in the lower Urodela and the Apoda it is rudimentary.' 

 Examples: Rana, Bombinatov, Bufo, Xenopns, Salamandva, and Spelerpes. 



Digestive System. — ' The alimentary canal is simple and nearly 

 straight in the Apoda and lower Urodela, but, in most cases, cardiac 

 and pyloric divisions of the stomach can be distinguished, and the 

 intestine is thrown into coils. The rectum is short and opens into a 

 cloaca, to the ventral side of which a urinary bladder is appended. 

 There are no definite salivary glands. The liver is usually two-lobed, 

 and the left lobe is subdivided in Anura. The liver is elongated in 

 the Apoda and in the more slender-bodied Urodela.' Then follow 

 dissections of the isolated alimentary canal of the frog and salamander, 

 and preparations of the liver of the frog, salamander, and Proteus. 

 ' The larvae or tadpoles of the Anura feed on vegetable matter, 

 whereas the adults live on insects, worms, etc. In relation to this 

 difference in diet the alimentary canal is not only relatively but 

 absolutely longer in the tadpole than in the adult ' ; a generalisation 

 which is illustrated by dissections of the alimentary canal of a tadpole 

 and an adult of Alytes. 



Vascular System. — ' In the heart of Amphibia the ventricle is 

 single but the auricle is divided by a more or less complete septum. 

 Of the four vascular arches of the larva, the first gives off the carotid 

 arteries and the fourth the pulmo-cutaneous arteries ; the second 

 arch persists as the aorta, while the third is lost in most cases but 

 frequently persists in salamanders. A post-caval, an anterior 

 abdominal and a pair of renal-portal veins are always present, but 

 the post-cardinal veins of the larva usually atrophy in the adult.' 

 Injected specimens of the frog and salamander, and preparations of 

 the heart oi Rana, Amphiuma, Siren, and Cryptohranchus serve to illus- 

 trate the vascular system, while a pair of dissections of the 

 subcutaneous spaces and lymph hearts of the frog show the excep- 

 tional development which the lymphatic system attains in the 

 Anura. 



Nervous System. — ' The brain of the Amphibia is elongated 

 and without any marked flexure. The olfactory lobes are sessile 

 and the cerebral hemispheres are large and elongated. The optic 

 lobes are larger and more clearly marked off from one another in 

 Anura than in Urodela. The cerebellum is a transverse bridge of 

 variable breadth, but always small in size. The hypoglossal is 

 usually the first spinal nerve. The dorsal and ventral nerve roots 

 unite outside the neural arch, and the spinal ganglia are surrounded 

 by calciferous glands.' Then follow three dissections of the nervous 

 system of the frog, and preparations of the brain of the frog, sala- 

 mander, axolotl, and Cryptobranchiis. 



Lateral Line. — ' The sensory organs of the lateral line occur 



