[40]

W O R K S OF d a r w i n : v o l u m e 1 4 the alae not being narrow, and from the inner ends o f the folded walls being, as it would appear, also broad, I have little doubt that the cavity in which the animal’s body was lodged, resembled in shape that in C. balaenaris, the membranous basis being larger than the orifice of the shell.