Distribution of Two Species of Conchoderma (Cirripedia : Thoracica) over the Body of a Sea Snake, Laticauda semifasciata (Reinwardt), from the Kii Peninsula, Southwestern Japan

Two species of Conchoderma were found on a sea snake, Laticauda semifasciata (Reinwardt), collected on the west coast of the Kii Peninsula. A total of 223 individuals of C. virgatum and 6 of C. hunteri in 19 clumps were attached to the snake's body. The barnacles ranged in size from 1.4 mm (cypris larvae) to 18.2 mm in capitulum length in C. virgatum, and from 10.7 to 14.4 mm in C. hunteri. The size of the smallest gravid individuals in both species was between 10 and 11 mm. The distribution of C. virgatum on the snake was non-random both longitudinally and dorso-ventrally, with more barnacles in the posterior region and on the ventral side of the snake, respectively. The proportion of gravid individuals increased towards the tail

STUDIES ON THE DAILY RHYTHMIC ACTIVITY OF THE SEA-PEN, CAVERNULARIA OBESA VALENCIENNES. -XVIII. ONTOGENIC DEVELOPMENT OF THE DAILY RHYTHMIC ACTIVITY-

1. The sea-pen, Cavernularia obesa VALENCIENNES, spawns in October and the eggs are fertilized in water and start to develop instantly. 2. In earlier stages of development they do not exhibit daily rhythmic activity. It appears on the 6th or 7th day after fertilization, when the tentacles just begin to differentiate. The daily rhythmic activity in the polyp stage is most remarkably shown by day-contraction and night-expansion of the tentacles. 3. The endogenous nature of the daily rhythmic activity was studied by putting the young polyps in constant darkness on the 6th, 9th, 15th and 20th day respect tively after fertilization. (i) The animals whose tentacles were differentiated in dark did not show any daily rhythmic activity. (ii) The animals, whose tentacles were differentiated in the normal day-night condition and placed in constant darkness on the 9th day after fertilization (after living under normal day-night condition for 2 or 3 days, with developed tentacles), persisted about one daily rhythmic activity cycle only. (iii) When the animals were placed in constant darkness on the 15th day after fertilization (after living under normal day-night condition for about a week, with developed tentacles), a stronger persistence of the daily rhythmic activity was observed (persistence was observed for 2 or 3 days in some case). (iv) It was impossible to get further concrete results because of difficulty of rearing the young animals in healthy condition for more than 20 days after fertilization. 4. It can be concluded that, (i) for the emergence of the daily rhythmic activity of the sea-pen it is necessary to be triggered by the environmental rhythms after the accomplishment of differentiation of organs related to the daily rhythmic activity, and (ii) the endogenous nature is more and more firmly settled in accord with the progress of development

An extraordinarily large specimen of the polychaete worm Eunice aphroditois (Pallas) (Order Eunicea) from Shirahama, Wakayama, central Japan

A large specimen of Eunice aphroditois (Pallas) (Annelida, Polychaeta, Eunicea, Eunicidae) was collected from a mooring raft for fish culture at Seto Fishing Harbor, Shirahama, Japan, on January 16, 2009. The raft had been in use for 13 years and the worm was hidden in one of its floats. This worm, measuring 299 cm long with 673 segments, and weighing 433 g, is one of the largest specimens of this species ever recorded from the temperate and tropical seas of the world

Many Records of Hermatypic Scleractinian Corals that Grew on Molluscan Shells

Forty cases of hermatypic scleractinian corals colonizing molluscan shells were recorded. Forty-five colonies of the corals belonging to eight genera in six families grew on 40 shells belonging to 15 genera in 12 families. Forty colonies were found in Tanabe Bay and its vicinity, southwestern Kii Peninsula, Japan, and 10 colonies in coral reef regions in Okinawa, Palau and probably the Banda Sea and/or the Arafura Sea. Usually one colony, rarely two to four colonies of at least two species of corals, grew on a shell of three families of gastropods and nine families of bivalves. Although the shell surface is a suitable substratum for planula larvae to settle down, coral colonies can not grow to large sizes on the shells. In most cases, shells may not be stable and sufficient substrata for continuous growth of corals. However, the corals on the shells may conduct the sexual reproduction to some extent. Unstability of molluscan shells as footholds may be one of the reasons why the association is not remarkable on the reefs