The descriptive morphological study of the gill is
dominated by the mitochondria-rich chloride cell
and its subtypes (Pisam and Rambourg, ’91; Ju¨rss
and Bastrop, ’95; Perry, ’97; Evans et al., ’99).
MRCs tend to be concentrated in the afferent
region of the filament epithelium and have an
intimate association with the arteriovenous circulation,
notably the central venous sinus, although
in the interlamellar region MRCs are also associated
with the basal channels of the lamellar
arterioarterial circulation (Laurent, ’84; Olson,
2002, this issue)