. The Columella auris in Amphibia. The Columella Auris in Amphibia. 583 amen which increases in size with the growth of the skull. The early ossification of the ear capsule renders impossible the fonnation of an operculum by either the cutting out process or by forward growth into the fenestral membrane. A comparison of Figs. 11 and 12 will help to make clear that the membrane filling the caudal portion of the fenestra corresponds in its position and relation to other parts to that portion of the fenestra in Ambystoma which is occupied by the operculum. This, together with the formation of a p
. The Columella auris in Amphibia. The Columella Auris in Amphibia. 583 amen which increases in size with the growth of the skull. The early ossification of the ear capsule renders impossible the fonnation of an operculum by either the cutting out process or by forward growth into the fenestral membrane. A comparison of Figs. 11 and 12 will help to make clear that the membrane filling the caudal portion of the fenestra corresponds in its position and relation to other parts to that portion of the fenestra in Ambystoma which is occupied by the operculum. This, together with the formation of a prominence by the fenestral membrane in this region, which when chondrified affords attachment for the M. opercularis, suggests that it is oper- cular tissue. Taking this view^ it is perhaps not inappropriate to consider that the caudal portion of the fenestral plate in the Pletho- dontidse represents the operculum of other Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Kingsbury, Benjamin Freeman, 1872-1946; Reed, H. D.
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Keywords: ., bookcentury1900, bookcollectionbiod, bookdecade1900, bookyear1909
