The excretory transport of toxic ammonia across epithelia is not fully understood. This review presents data combined with models of ammonia excretion derived from studies on decapod crabs, with a view to providing new impetus to investigation of this essential issue. The majority of crabs preserve ammonotely regardless of their habitat, which varies from extreme hypersaline to freshwater aquat...

We compared the sensitivity of algae and hermit crabs to seasonal shifts in the dominance of continuous sewage discharge vs. pulsed inputs of terrestrial material to a subtropical bay. During periods of low rainfall, when sewage was proportionately more important than diffuse loads from adjacent catchments, algae and crabs provided comparable information on the spatial distribution of N polluti...

Animal pain is defined by a series of expectations or criteria, one of which is that there should be a physiological stress response associated with noxious stimuli. While crustacean stress responses have been demonstrated they are typically preceded by escape behaviour and thus the physiological change might be attributed to the behaviour rather than a pain experience. We found higher levels o...

ALTHOUGH the physiological and mechanical phenomena of the vasa deferentia resulting in the elaboration of the spermatophores of marine hermit crabs (Pagurida) have been investigated (Mouchet, 1931; Matthews, 1953), these phenomena in terrestrial hermit crabs (Coenobita and Birgus) have been neglected. Spermatophores of marine hermits are made with precision; the so-called immutable form of the...

During the last thirty years there has been a large volume of work published on the osmotic behaviour of invertebrate animals (recently reviewed by Kinne, 1964 and Potts & Parry, 1964), of which much has concerned the Brachyura (see reviews by Robertson, i960 and Lockwood, 1962). Most of this attention has been directed towards what can be termed 'a purely physiological end-point', comparativel...

Recent scientific interest following the "discovery" of lithodid crabs around Antarctica has centred on a hypothesis that these crabs might be poised to invade the Antarctic shelf if the recent warming trend continues, potentially decimating its native fauna. This "invasion hypothesis" suggests that decapod crabs were driven out of Antarctica 40-15 million years ago and are only now returning a...

The basic arrangement of limbs in euarthropods consists of a uniramous head appendage followed by a series of biramous appendages. The body is divided into functional units or tagmata which are usually distinguished by further differentiation of the limbs. The living horseshoe crabs are remnants of a much larger diversity of aquatic chelicerates. The limbs of the anterior and posterior division...

Blue crab diseases, parasites, and commensals are not well studied in the Gulf of Mexico, and their prevalence rates have only been sporadically determined. Commercial soft shell shedding facilities in Louisiana experience high mortality rates of pre-molt crabs, and some of these deaths may be attributable to diseases or parasites. During the active shedding season in 2013, we determined the pr...

Amiloride-sensitive Na+/H+ exchange in plasma membrane vesicles prepared by sucrose density gradient centrifugation of mitochondria-rich posterior gill cells in two species of crabs (Callinectes sapidus and Carcinus maenas) was examined by acridine orange fluorescence quenching. Sodium-loaded vesicles injected into sodium-free incubation medium (pHout = pHin) caused a quench in fluorescence ind...

Hypoxia or dissolved oxygen concentrations < 2 mg/L is a problem in estuaries worldwide. In Lake Pontchartrain, a 250 km de-faunated zone exists as a result of salinity stratification and episodic hypoxia. Mature common rangia clams (Rangia cuneata) are not found within this zone. Blue crabs (Callinectes sapidus) are important estuarine predators and may move in and out of the hypoxic zone to f...