BATR. GRADIENTIA : DOUBTFUL SPECIES. 49 
Animals apparently of this Suborder, which have only been 
observed in ther Larva state. 
1. Axotott Cuvier, R. A. 11. 119.; HMumb. Obs. Zool. Oss. Fos. 
v. 1811; Mayer, Anal. 87.; Home, Phil. Trans. 1824. | 
Gyrinus Hernand. N. 8. 77.; Shaw, Nat. Mise. ii. 313. (not 
Linn.) 
Siredon Wagler, Icon. t.20. Syst.; Tschudi, Batrac. 97. ; Fitz. 
S. &. 34. 
Phyllhydrus Brook, Cat. Mus.; Gray in Griffith's A. K. 1x. 108. 
Triton Larva? Gray, Ann. Phil. 1825. 215. 
Molge Larva Merrem, Tent. 187. 
Piscibus ludicus seu Axolotl Hernand. Hisp. 76. 
Gyrinus edulis seu Atolocatl Hernand. Anim. N. Hispan, 77. 
Phyllhydrus pisciformis Gray, Griff. A. K. ix. 108. 
Siredon Axolotl Wagler, Icon. Amph. t. 20. 1833; Tschudi, 
Batr. 9.; Fitz. S. R. 34. 
Proteus seu Larva Salamandre, Mexicanis Axolotl, Cuv. Humb. 
Zool.i. 109. t. 12.14. f. 10. 16. 
Axolotl Home, Phil. Trans. 1824, 519. t. 21. 23.; Cuvier, Oss. 
Poe wate 27. 1. 24,.95., A. A. i.119. 
Siren pisciformis Shaw, Zool. iii. t. 140. f.12. 1802. 
Gyrinus mexicanus Shaw, Nat. Misc. t. 313. 1800. 
Molge giganteus junior Merrem, Tent. 187. 
Axolotus mexicanus Cuvier; Ribron, Mus. Zool. Soc. n. 674. 
Axolotes guttatus Owen, Ann. and Mag. N. H. xiv. 23. , 
Hypocthon pisciformis Gravenh. Del. Mus. Urat. 84. 1829. 
Siredon mexicanus Baird, |.c. 292. 1849. 
Anat. Cuvier in Humboldt's Obs. Zool. t. 12.; Home, Phil. 
Trans. 1824; Cuvier, Oss. Fos. v. 418. t. 27. f. 24, 25. 
Ostrou. Cuvier in Humboldt, Obs. Zool. t. 14. f. 10—16. 
(skeleton). 
a—c. In spirits. Mexico. Mr, Brandt’s collection. 
The skull, t. 3. f. 12., copied from Cuvier, Oss. Foss. t. 27. f.25., 
differs very little from that of the young Triton marmoratus, which 
had not gained its second pair of legs, figured t.2. f. 10. from 
Duges, t. 14. f. 89. 
“It (Siredon) so much resembles the larva of Ambystoma 
punctata, in both external form and internal structure, that I can- 
not but believe it to be the larva of some gigantic species of this 
genus. It differs from all known Perennibranchiates in possessing 
the larval character of the gular or opercular flap, this being unat- 
tached to the subjacent integuments, and free to the extremity of 
the chin. The nondiscovery of the adult is no argument against 
c 
