210 



COMPARATIVE ANATOMY. 



D 



Ki<;. 171. - DIACKAMS OF TIIK OI:AI, CAVITIES OF A IMSII (A), AMPHIBIAN (B), 



Kr.rrn.K <>i: Ilinn (( !), AND .MAX (D). 



.Y. c\li-in;il iK'siiils; I'll, internal nostrils: D, alimentary canal; K, gill-slits; L, 



liin^' ; T, trarln-a; a, fi'siniha^iis: the:i]Tn\\ marked A indicates the respiratory 



i^'c, tliat niarked /.' the nutritive jinssa^e ; t, the point where the two 



rs cross illle illiother. 



