Cannulae combined with electrodes were devised for simultaneous recordings of intracardiac blood pressures and electrocardiograms from the carp ranging from 700 to 1, 000 g in body weight.Cannulae were implanted at any two of three sites: dorsal aorta, bulbus arteriosus and ventricle.Size of cannula, site of cannula implantation and type of transducer adequate for the blood pressure measurements were investigated. In the confined but not anesthetized, systolic blood pressures in the bulbus arteriosus were either equal to or slightly less (about 1.0 mmHg) than those recorded in the ventricle.Pulsating pressures were much less in the bulbus arteriosus than in the ventricle.As in other fish, carp also showed a less of pressure across the gill vasculatre, and the loss amounts to about one-third of that generated by the heart.In an undisturbed state, heart rate became low and nonrhythmical.Ventricular contractions were performed in small group with short pauses between series.

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In all native American cyprinids the supraorbital and infraorbital lateralline canals of the head are separate.American forms differ in this feature from tropical cyprinid groups but agree with the leuciscines of temperate Eurasia.Within the leuciscine cyprinids, particularly close resemblances in head canal patterns between Eurasian and American genera are shown by Leucaspius and Notemigonus, by Tribolodon and Lavinia, and in the Phoxinus-Moroco-Chrosomus complex.

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Secondary sexual characters of Bothus pantherinus (Rüppell) were examined.An abnormal specimen, among109normal specimens, had mosaic characters of both sexes.In the histological observation, the gonad was consisted mostly of testis, but in part ovarian tissue was recognized.The specimen may be considered as an abnormal intersex.

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Present paper deals with ecology, behavior, and life history of Sacura margaritacea (Hilgendorf) in Suruga Bay.The species, which is sexually dimorphic and protogynous hermaphroditic fish belonging to the subfamily Anthiinae, ranges from Sagami Bay to Nagasaki along the Pacific coast of Japan.Its size is usually less than 13.0 cm in standard length.The investigations were performed using SCUBA, and were conducted mainly at two stations mostly shallower than 48 m deep (Figs.1 and 2).The stations were visited for two to five days in every month during two years, 1971-1973.After the each underwater observation, live specimens were captured for the observation in the laboratory.
S.margaritacea is found mostly in large schools in the subtidal rocky habitats more than 15 m deep (Fig.2), though few individuals were in the depth as shallow as 7 m.The schools of the fish extend to shallower area in summer, and return to deeper area late in autumn to spring.The males swim closer to sea-bottom where as the females swim around to the middle layer apart from the bottom (Fig.7).
Among 364 specimens captured, 296 were females, 79 were males, and 19 wereintermediate in sex reversal.In fork length females were in the range 64.4-124.0 mm, males were 117.5-146.0 mm, and intermediates were 111.1-127.0 mm and extremly rare (Table 2 and Fig.3).No monthly change in sex ratio through the year were observed excepting appearances of the intermediate forms (Fig.5).
Spawning season of the fish starts in August, reaches climax in September, and falls in November (Fig.6).Previous to the breeding season, a few individuals of both male and female make small groups together near the shallower bottom (about 15 m deep) at the stations.Then, the males perform the display dance toward selected females.In August, when the breeding season draws, the display by males become more active, and is frequently observed everywhere in schools.However territorial behavior are indistinct in this species.
The sex reversal in S.margaritacea takes place in the range 111.1 mm-127.0 mm in fork length and occurs mainly during the non-breeding season.
Youngs of S.margaritacea smaller than 64-65 mm in fork length are not included in schools.Youngs measuring 19.5-54.8 mm in fork length (Fig.8) were found behind the rock on sea-bottom 15-48 m deep near circumferrences of schools.Youngs were presumably younger than a year old.These Youngs appear to join schools in early summer in the next year, and to reach biological minimum size as female in one or two years after hatching.
S.margaritacea is a plankton feeder, and mostly feeds on calanoid copepods throughthe year in Suruga Bay.
Artifically fertilized eggs of the fish are bouyant, colorless, spherical, and measuring 0.78-0.80 mm in diameter.The hatching takes place 15.5 hrs after insemination, at the water-temperature of 24.3-28.5°C.The newly hatched larva, measuring about 1.46-1.52 mm in total length, has an oil-globule situated in the anterior top of yolk.The larva has 13+13=26 myotomes and the fish has 26 vertebrae.Larvae of 48 hrs after hatching are 2.40-2.46mm in total length.In this stage the posterior part of eye is black, and the mouth is open (Fig.12).
The newly hatched larvae of S.margaritacea have some remarkable features and differ from the previously known larvae of other Japanese serranids, such as Lateolablax japonicus and Epinephelus akaara.The larvae of S.margritacea have a large and oval yolk protruding anteriorly beyond the anterior point of head.Also the larvae float with the head upward.Whereas larvae of the two serranids mentioned above do not have such a large yolk, and float the head downward (Mito, 1957;Ukawa et al.1966).

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[in Japanese]

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[in Japanese]

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Estimation of gill ventilation volume was based on the Fick principle using P_o2, difference between inspired and expired waters and the rate of oxygen consumption (Figs.1 and 2).The minute volume and stroke volume of resting unanaesthetised tench inspiring well-oxygenated water was 243-530 ml/kg min and 9.1-13.9 ml/kg, respectively (Table 1).Both minute volume and stroke volume increased and O₂ utilization decreased greatly during hypoxia.The increased ventilation is considered to contribute to respiratory homeostasis during the early stages of hypoxia (Fig.3).

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