abdominal lung

The gills of Coenobita and Birgus are modified for air-breathing but are reduced in number and size and have a comparatively small surface area. The branchiostegal lungs of Coenobita (which live in gastropod shells) are very small but are well vascularized and have a thin blood/gas barrier. Coenobita has developed a third respiratory organ, the abdominal lung, that is formed from highly vascularized patches of very thin and intensely-folded dorsal integument. Oxygenated blood from this respiratory surface is returned to the pericardial sinus via the gills (in parallel to the branchiostegal circulation). Birgus, which does not inhabit a gastropod shell, has developed a highly complexRead More →