CULTIVATION OF THE TURBOT. 865 



In 1904, L. Dantan," repeating these experiments, obtained an identical result 

 at the same laboratory. In both cases the hatching took place normally, but 

 unfortunately all the larvae died a few days later, not being able to survive the 

 critical stage. Thus only the first part of the problem was solved. 



In 1905 Fabre-Domergue and Bietrix (op. cit.) published their memoir on 

 the development of the sole. No hatches of turbot or sole could be obtained 

 in the laboratory of Concarneau where these authors operated. Fabre- 

 Domergue and Bietrix were obliged painstakingly to collect eyed eggs of the 

 sole in the sea. But they were able to bring a small number of individuals far 

 beyond the critical period. For the sole, at least, the second part of the scientific 

 problem was realized. In 1905 Malard and Dantan, who had obtained normal 

 hatches of the turbot, had not been able to carry their larvae past the critical 

 period, and Fabre-Domergue and Bietrix, who had not been able to obtain 

 hatches, had carried the sole through the critical period. With the turbot, 

 rearing past the critical period had not been accomplished. 



In the course of 1907 we were more fortunate at the laboratory of St. Vaast- 

 la-Hougue than in 1898 and in 1904, and succeeded not only in making the 

 larvae live beyond the resorption of the umbilical sac, but in obtaining after this 

 critical period a considerable increase of volume and an important modification 

 of the shaj>e. The conditions under which I obtained these results are the fol- 

 lowing : 



During the month of February, 1907, I procured 10 adult turbots, which I 

 placed in the large hatching basins of the laboratory. These basins, constructed 

 according to the directions of Mr. Edmond Perrier, are three in number. The 

 capacity of the largest is more than 300 cubic meters. They are filled by means 

 of a pump, worked by a windmill, or a gasoline motor when the wind is not 

 sufficiently strong. This pump brings the water to the upper part of the basin. 

 A waste pipe is in the lower part. In the middle is an incomplete trench about 

 the depth of a stair step, made after the design of A. E. Malard, to promote the 

 spawning of the females, which this author found rubbed their abdomens against 

 its acute angle. The basins are covered with a thatched roof and are amply 

 lighted. 



Let us note that so far there exists no certain external means of recognizing 

 the sex of the turbots when alive, although many naturalists have endeavored 

 to find it. Nevertheless, taking 12 individuals, there are great chances of having 

 both females and males among them. The only thing to remember is that the 

 fish should not be less than 40 centimeters in length. With smaller individuals 

 there would be a risk of their not yet being mature. 



"Dantan, L.: Notes ichthyologiques. Archives de Zoologie e.xperimentale et generale. Notes 

 et revues, 1905. 



