HETEROBLASTIE. I I I 



Cephalopoda. At one point, a small laboratory for the investiga- 

 tion of fisheries problems is established. 



At Kawana, in the province of I/ai, Dr Kishinouye is trying 

 experiments on the cultivation of Haliotis. 



Sardines are caught all over Japan, and form one of the most 

 important fisheries products. But the coast of Kujukuri, in the 

 province of Shimosa, is specially famous for the immense quantity 

 of the catch, as well as for the huge dimensions of the nets used. 



The warm Black Current is removed further and further from 

 the shore as we go northward, and between it and the coast there 

 comes down a cold northern current, which reaches down, in the 

 colder season at least, as far as Cape Inub5zaki. In the northern 

 part of Japan, many northern fishes like the cod, salmon, herring, 

 and others are thus found. 



Two bays — one in the extreme south, the Bay of Kayoshima, 

 and the other in the extreme north, the Bay of Awomori — are 

 famous for their abundance of Pectens. The southern form is Pecten 

 laqueatus, and the northern Pecten Yessoensis — the latter attaining 

 a very large size. 



The Strait of Tsugaru forms one of the marked boundary-lines 

 in the distribution of animals, the fauna of Yeso being allied in 

 many respects to that of the continent and different from that of 

 the islands south of it. 



In Yeso or the Hokkaido, the salmon, the trout, the cod, and the 

 herring are found in immense quantities, and are of the greatest 

 economic importance. The Bay of Hokodate is also famous for its 

 species of Brachiopoda. A small marine laboratory has recently 

 been established by the Hokkaido Fisheries Bureau. 



Prof W. Salensky, of St Petersburg, read the following paper 

 on 



HETEROBLASTIE. 



Verschiedene Forscher auf dem Gebiete der Embryologie der 

 Ascidien und der Wirbeltiere haben einen bedeutenden Unter- 

 schied in der Entstehungsweise des Herzens und des Pericardiums 

 bei den beiden eben erwahnten, sonst nahe verwandten, Tier- 

 gruppen hervorgehoben. Aus den Untersuchungen von Seeliger 

 und von E. Van Beneden und Jnlin, welche von mir bestatigt 

 wurden, geht namentlich hervor, dass das Pericardium und das Herz 

 der Ascidien nicht aus dem Mesoderm, wie es bei VVirbeltieren der 

 Fall ist, sondern aus dem Entoderm ihren Ursprung nehmen, 

 Diese Eigentiimlichkeit der Entstehung des Herzens hat einen 

 um so grosseren Wert, als bei alien iibrigen Tieren ohne 

 Ausnahme diese Organe aus dem Mesoderm entstehen. Man 

 konnte noch hoffen, dass die ungeheuere Kluft, welche zwischen den 

 Wirbeltieren und den Tunicaten in dieser Beziehung zum Vorschein 

 getreten ist, durch den Nachweis der entodermalen Entstehung bei 



