BULLETIN OF THE UNITED STATES FISH COMMISSION. 239 



were carried into a colli room ^Yitllout sniisliinc, they went 2 to 4 centi- 

 meters [about 1 inch] below the surface of the water. By letting a fine 

 shower of fresh water fall into the vessel iiom a sprinkler, the little 

 oysters immediately stopped their movements and went a little below 

 the surface of the water. By continuing the sprinkling, a layer of fresh 

 water formed at the surface, and the little oysters could be seen going 

 down until this layer had reached a thickness of 5 to G centimeters 

 [about 2 inches]. At the end of the thirteenth and fourteenth day the 

 shells and potsherds which had been placed at the bottom of the vessel 

 were so thickly covered with young oysters that it would have been 

 <lifficult to insert a ])in anywhere." 



We have several tiujes attempted this experiment, following in every 

 l)articular the directions given in the communication of Mr. Schmidth, 

 but without obtaining any result.* 



* III a report made to tLo minister of public iustrnction, in 1878, wo gave au ac- 

 couut of experiments similar to those made by General Wergeland in a bay near 

 Cbristiania, in latitude about 59° nortli, and stated the follo^Yin;J;: 



It was necessary to counteract the inlluenc(! of an early and severe winter, of weak 

 tides (which at the most reach the height of only a foot or a foot and a half) and 

 the violent storms which sometimes move masses of water more than 7 feet high. 

 When the winter comes on in Norway, about the beginning of September, the spawn 

 is still too young to resist the great and snddeu changes of temperature. It was, 

 therefore, of the utmost importance to keep it from contact with the outer air. 



In the upper part of the establishment a reservoir of supply was constructed, filled 

 by a pump worked by a windmill. Immediately below, and inside a shed, which in- 

 sured protection against the severity of the cold, the spawning basin was constructed, 

 8 meters long and G meters broad [20^ by lOg- feet]. A metal pipe, furnished on the 

 upper side with a fine grating to keep out hurtful animals, and on its lower side 

 with stop-cocks to regulate the llovr of the water, connected the two reservoirs. This 

 pipe turned several times on itself, and passed through a chamber tilled with water, 

 which could lie heated, if necessary, so as to keep at an almost even temperature 

 the water feeding the spawning basin. The level of this basin was regulated l)y 

 a tube, to the mouth of which was attached a filter destined to prevent the spawn 

 from escaping. In this covered, basin the mother oysters, to the number of 2,200, 

 were placed in the beginning of the season ; and although they had undergone the 

 fatigue of a long journey, they emitted enough spawn for some of it to be found on 

 the collectors by which they were surrounded. 



In addition to this we have to state the following: 



M. Bonnasset, an oyster cultivator of Mareunes, succeeded two years ago in obtain- 

 ing same spawn, which had come from some very fine oysters, in a clairc which he 

 had devoted to this purpose, by ijlaciug some mother oysters in a brook which fed 

 this clairc. The spawn carried along by the current attached itself to shells found 

 at the bottom of the reservoir. This is not a rare occurrence. It has l)een observed 

 in the pond of Brdn(5guy, near Auray, where, during the first year the oysters were 

 placed there, a very hue reproduction was obtained, although the water of this pond 

 was renewed only when there was a spriug-tide. 



A similar occurrence was observed in the ponds constructed by Mrs. Sarah Felix, 

 at Rdgndville, when these ponds were first worked. Unfortunately, the harvest 

 reaped under similar conditions is exceedingly uncertain, for it has been observed, 

 that oysters living in close waters hardly ever propagate. This is not the case in the 

 claircs of Marennes, wljere the oysters regularly fulfil their generative functions, but 

 is so in the two other establishments mentioned above. 



