370 CLASSIFICATIONS OF THE AMPHIBIA. 



tion maybe named branchipulmonary, that is, both branchial 

 and pulmonary; and therefore either the one or the other 

 takes place as the respiration of the animals is aquatic or at- 

 mospheric- In this sub-class are comprised two orders. 



The third order, — Imperfectibranchia, — is provisionally 

 instituted in consequence of our present imperfect knowledge 

 of the two American genera, Menopoma and Amphmma, 

 which alone constitute it. 



These extraordinary creatures appear to have only imper- 

 fect gills, or rather gill-like organs, for they are not known to 

 possess the external branchial tufts, which permanently be- 

 long to, and form the chief character of, the following order, 

 though they are always furnished with the rest of the gill-like 

 apparatus, viz., the branchial openings on the sides of the 

 neck, the membranous lids or opercula, and cartilaginous arc 

 formed from the hyoid bone. From a careful examination of 

 these organs in the beautiful specimens of the anterior por- 

 tions of the Amphiuma means 1 and the Menopoma Allegha- 

 niense, 2 prepared by the celebrated John Hunter; and after 

 attentively comparing them with the very similar parts in the 

 Proteus 2 and Sire?i, 4 I think I have sufficient grounds, dur- 

 ing our present confined knowledge at least, for maintaining 

 that they, in all probability, do some service analogous to the 

 true gills of the latter, and that they assist in, if they do not 

 altogether perform, the function of respiration in the water. 

 I was unable to perceive any particular difference in the struc- 

 ture of the branchial, pulmonary (except as to the origin of 

 the pulmonary arteries), and circulatory organs, between the 

 Amphiuma and the Menopoma, as exhibited in these speci- 

 mens ; wherefore the description of those organs in the one, 

 will suffice for both the animals. Mr. Hunter, in his own 

 account of the dissected specimen of the Amphiuma means 

 just referred to, and which is lately published in the ' Physi- 



1 Numbered 915 in the Museum of the Royal College of Surgeons in 

 London ; described in the ■ Phys. Cat.' vol. ii. p. 43 ; and figured in Rus- 

 coni's ' Amours des Salamandres,' pi. 5, fig. 7, where it is named by mistake 

 " Siren lacertina." See Hunter's own description of it in Cat. vol. ii. p. 

 150, note. 



2 Numbered 916 and 917 in the same Museum; described in Cat. vol. 

 ii. p. 45 ; also therein figured in plates 23 and 24. For Hunter's account 

 from his MS., refer to the same Cat. pp. 149 — 154. 



3 Vide ' Monografia del Proteo,' da Configliachi e Rusconi ; tab. 4, fig. 

 8: 1819. 



4 See preparation No. 914 in the Museum of the Royal College of Sur- 

 geons, and the plate illustrative of Prof. Owen's paper in vol. i. of the Zo- 

 ological Transactions. Also plate 11, part 2, vol. i. Voyage de Humboldt 

 et Bonpland. 



