| Each posterior spiracle has three openings or slits arranged parallel or converging, on a sclerotized plate. |
| The plastron is actually a modified air storage chamber that consists of air in a series of cuticular grooves radiating from a spiracle. |
| H are seen the long filiform external gills which now project out from all the visceral clefts, including the spiracle. |
| Small capitate processes or organs, observable under the wings of Diptera, attended by a spiracle. |
| Most sharks and all rays have an opening behind each eye, called a spiracle, which is a modified first gill cleft. |
| The nasal opening of whales and other cetaceans is called a spiracle, as is the respiratory opening behind the eyes of rays and skates. |
