Organs subservient to respiration through medium of liquid.
In Arthropoda, as crustaceans, particularly, the externally projecting procedures of this human anatomy or its limbs, which are provided with venous blood (that will be thus brought into experience of air dissolved in water), and represent a particular respiratory organ. See cut under Podophthalmia.
In Vermes, any appendages of this head or human body therefore customized on become a respiratory organ; the many processes which protrude or radiate from the head or any other area associated with human body, and also, or are meant to have, a respiratory function. See cut under Protula.
In entomology, gill-like appendages in the figures of particular insect-larvæ and -pupæ which live-in water, as numerous dragon-flies and gnats.