In this paper are given notes on, or descriptions of, some interesting or rare fishes, including one new genus and three new species from Japan, the Ryukyus and Pescadores (Formosa Strait.) The specimens observed are deposited in the Zoological Institute, Faculty of Science, University of Tokyo, or in the Biological Laboratory, Imperial Household. Before going farther, the author wishes to express his hearty thanks to His Majesty the Emperor of Japan, who has willingly lent him the specimens of Pseudocepola taeniosoma KAMOHARA and Osbeckia scripta (LINNÉ) and the holotype of Mars auropunctatus n. sp.; all these specimens were collected by His Majesty himself from the eastern part of Sagami Bay. The author is indebted to Mr. Masao YOSHIDA of the Misaki Marine Biological Station for his assistance in examining the sexual differences in Monacanthus cirrhifer TEMMINCK et SCHLEGEL, and to Mr. Tsugio SAITO of the Imperial Household, who was kind enough to take the photographs of the specimens of the same species. The author is much obliged to Dr. Jean Clark DAN for her kindness in correcting the English of the manuscript.
This is a part of a series of experiments, which have been carried on to see the influence of environmental conditions to the activity of locomotion of fish. Measuring how frequent the fish would cross an assumed central septum of the tank to express the activity of fish-author is using the term of “frequency of transfer” to denote it - under various conditions. This time, the experiments were done to see the activity of gold fish, expressed by “frequency of tranfer, ” in various size of the. tank, which were obtained by changing a length of the same long tank by moving one septum from one end to the another of the tank (Fig.1) A series of experiments were undertaken by the following order. At first, whole length (150cm) of the tank is used and “frequency of transfer” is obtained. Next by shortening the length of the tank, one by one the same tank was utilized as smaller four size tanks, and in each case the same experiment was made until the length of tank is 37cm. After these, on the contrary, in the same degree of length, the four experiments were done one by one until the length of the tank became whole length. This one series of the experiments were repeated five times. And about the “frequency of transfer” in each series of experiment the average obtained for each size of the tank respectively as shown in Table 1 and Fig.2 and 3. Examining these figures, it is recognized that the “frequency of transfer” has a fair straight line relationship with the length of the tank as shown in Fig.3. However, when the length of tank is going to be shortened it has more figure of “frequency of transfer” than when it is going to be enlarged (Fig.2 & 3). This is considered that the speed and the distance of the fish swimming around here and there is almost constant so the activity of fish, when it is expressed as “frequency of transfer, ” would be the more in the smaller tank than the larger tank. And when the experiments were carried on in the order of shortening the length of tank, the fish is more actively moving than when it is in order of enlarging the tank. This straight line relationship tells us that no effect of change of other enviromental conditions happens during this series of experiments.
The part four of this article contains descriptions of life colors of the species nos. 59-76, with some interesting notes on the fishes found in Suruga Bay and others. The interesting species are as follows: Arengus sagax with notes on the variations of spottings on the body; characteristics of Parasalanx ariakensis from N. Kyushu; variations of members of anal organs found in eleven species of the Lantern-fishes of Suruga Bay; life color of the sea-run form of Triborodon hakonensis.
In the A-series, thirty chum salmon alevins were immersed in the solution of 1/1, 000, 000 of thyroxine and 1/3, 000 of thiourea, respectively, for six weeks immediately after hatching, and in the B-series, thirty alevins were immersed in the solution of 1/1, 000, 000 of thyroxine for seven weeks, one week after hatching, the effects of these treatments to salmon larvae were observed. The same number of control groups were held in tapwater under identical conditions. The following results were obtained: 1. In the both series of treated larvae, a marked inhibition in weight increase namely, the growth rate and also a delaying of the rate of absorption of yolk sac were observed. In the body form of the larvae treated by thyroxine, the broadening of the head, such as protrusions on the top of the head as well as posterior edge of the opercular and enophthalmos like conditions, was observed. But the developments of thetrunks, caudal, and fins, except elongated pectoral fins, were very poor. These modifications were more remarkable in the B-series. The marked changes were not observed in the larvae treated by thiourea, besides the immature characteristic which were somewhat kept in the body form. 2. In the both series, the colorlation of the larvae treated by thyroxine showed a pallor, namely, premature silverication, which was produced by the deposition of excessive guanine. On the other hand, the coloration of the larvae treated by thiourea showed no change. 3. In the control fish, the histology of the thyroid gland showed a figure of functional and hyperactivity with cuboidal epithelium and vacuolized colloid. On the contrary, the thyroid gland of the larvae treated by thyroxine in the both series appeared in the hypofunctioning figure with flattened epithelium and dense colloid. While the thyroid of the larvae treated by thiourea revealed pathological hyper functioning with obvious hypertrophic columnal epithelium, number increase and size decrease of follicles, and lack of colloid. Furthermore, hypertrophic cells of pituitary also observed in the thiourea treated fish.