504 BULLETIN 34, UNITED STATES NATIONAL MUSEUM. 



Fig. 3. Hyoid apparatus of adult, from below. 



4. Skull of larva, from above. 



5. Skull of larva, from below. 



6. Hyoid apparatus of larva, from above. 



7. Basis crauii of very young larva. 



PLATE XL. 



Urodela, viscera isolated and much enlarged. From drawing by Prof. S. F. Baird. 



Fig. 1-2. Spelerpes ruler, kidney and vas deferens, J . 



1. The tubules of the kidney displayed from above ; a, in greater detail 



from below. 



2. The vasa eflferentia ; diagrammatic. 



3. GyrinopMlus poiphyriticus, liver and central circulatory system of a large 



larva. 



4. Plethodon glutinosus, 2 , liver, natural size. 

 5-9. Diemyctylus viridesceiis, 5 • 



5,6. Reproductive organs and cloaca of male. 



7. Eight corpus adiposum, inferior surface, X 4. 



8. Testis. 



9. Kidney, vas deferens, and vasa eiferentia. 



PLATE XLI. 



Central nervous system of Urodela, enlarged. 



Fig. 1. Spelerpes ruber, from above ; a, from below. 



2. AmMystoma punctatiim, 9 , brain and cranial nerves of the left side from be- 



low. The cranial nerves are numbered. G, Gasserian ganglion ; Co, con- 

 necting branch between trigeminus and facial nerves; X, part of labyrinth. 



3. Diemyctylus viridescens, brain, from above ; a, from below ; h, from left side; 



Pe, prosencephalon ; Ep, epiphysis ; TE, thalamencephalou ; ME, mesen- 

 cephalon ; EE, epencephalon ; IV, fourth ventricle ; Hyp, hypophysis. 



4. Diemyctylus viridescens, semicircular canals. 



PLATE XLII. 

 Larval and breeding stages of Salamanders. 



Fig. 1. GyrinopTiilus porphyriticus larva, natural size; June 3. 



2. Spelerpes longicaudus larva X 4 ; May 29. 



3. Diemyctylus viridescens, breeding male, natural size ; a inferior side of hind leg, 



showing corneous nuptial excrescences, and tips of digits. 



PLATE XLIII. 



Siren lacertina, skeleton from below, two-thirds natural size. 



PLATE XLIV. 



Siren lacertina, splanchnology ; three-iifths natural size. 



For lettering see general explanation. The mesentery is divided so that the ali- 

 mentary canal can be extended outward to the right side, so as to display the 

 other organs. The lines VM and Mes, on the right of it, extending from the testes to 

 the gall-bladder represent the borders of the gap opened by the section. The 

 cloaca is divided, exposing the mouths of the urethra and ureters. For heart and 

 vessels see Plate 19, fig. 5. 



