Tilupiu nilotica reaches maturity in the first year of life; females mature shortly before males (11.4 and 14.3 cm in length). The distinctive morphological features of the different stages of development of the gonads are characterized. The sex ratio vaned in populations of different age (size)-groups: a ratio of 2.81 : 1 and 0.47 : 1 (females : males) was obtained in populations of young and old fish. In medium-sized populations the sexes were equally abundant. There is evidence that females breed more than once a season. Fecundity varied more with body length (r=0.860) and weight (r=0.806) than with age (r=0.604). These variations were of the order of 2.02; 0.83 and 0.83 exponentials of length, weight and age, respectively.

The relative dependence on branchial and pulmonary organs was studied in the African lungfish P. annectens and in the catfish Clarias lazera . The frequency of pulmonary ventilation varied, in the normal state, with the activity and age of the fish and followed a circadian rhythm. Small specimens of both species exhibited a higher branchial ventilatory rate than older specimens and depended largely on aquatic 02 uptake (over 85% and 9o% in Clarias and Protopterus respectively). The dependence on aerial respiration appeared to develop gradually with age in Clarias but occurred over a limited age-range (200-300 g) in Protopterus. In mature fish (over 400 g), pulmonary respiration constituted 50-60% of the total in Clarias and 80-85% in Protopterus . Partitioning of 02 uptake between air and water depended on the 02 content of the water and that of 0 2 and CO2 in the pulmonary organs . Protopterus and Clarias surfaced for air when the 0 2 content of the respiratory organs was reduced to 9o% and 85% (of that immediately following an air-breath) respectively. An increase in the pulmonary 0 2 content lengthened the apnoeic period and reduced pulmonary respiration more markedly in Protopterus than in Clarias whereas an increase of that of CO2 produced the reverse effects .

Patients with MERS-CoV infection showed variable hematologic parameters over time. Lymphocytosis and neutropenia were not features of MERS-CoV infection.

Low doses of arginine-vasotocin (AVT), isotocin and oxytocin (1 pg-1 ng/kg body weight) were antidiuretic in eels adapted to fresh water but not in those adapted to sea-water. High doses (more than 10 ng/kg) were always diuretic. No effects on tubular water reabsorption were observed and the glomerular filtration rate (GFR) was proportional to the maximum reabsorptive rate for glucose (Tm(glucose)) in eels adapted to sea-water. Increases in urinary flow appeared therefore to result from glomerular recruitment. Infusion of AVT or isotocin at low rates reduced the GFR and urinary flow of freshwater eels to the levels found in seawater eels. Vasopressin (lysine or arginine) had no direct effect on kidney function in freshwater eels but blocked both the diuretic and antidiuretic actions of the other hormones. When infused into seawater eels it was diuretic. This effect could have been due to blockade of the actions of endogenous AVT and/or isotocin.

The respiratory behaviour and partitioning of 02 uptake between air and water were investigated in Polypterus genegalus using continuous-flow and two-phase respirometers and lung gas replacement techniques. P. senegalus rarely resorts to aerial respiration under normal conditions. Partitioning of 02 consumption depends on the activity and age of fish and the availability of aquatic oxygen. Immature fish (12-22 g) cannot utilize aerial 02 but older fish exhibit age-dependent reliance on aerial respiration in hypoxic and hypercarbic waters. Pulmonary respiration accounts for 50% of the total requirement at aquatic 02 concentrations of about 3.5 mg 1-' (or CO 2 of about 5%) and fish rely exclusively on aerial respiration at 02 concentrations of less than 2.5 mg 1-. Branchial respiration is initially stimulated by hypercarbia (CO 2 : 0.5-0.8%) but increased hypercarbia (CO 2 -1%) greatly depresses (by over 90%) brancial respiration and initiates (CO2: 0.5%) and sustains pulmonary respiration.