228 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



of M. Laureut, director of the Transatlantic Company. These re- 

 searches were made under the direction of Pierre Laurent, the son of the 

 learned director, a summary account of whose labors is here given. 



Report of Pierre Laurent. — Our parks at Pouliguen are located 

 in the old abandoned salt marshes Avhich have been appropriated for the 

 cultivation of oysters and tish. The water is brought into them by a 

 canal 500 meters [1,G40 feet] long, v.iiich opens in the harbor of Pouli- 

 guen. There are gates which allow the different reservoirs to be emjitied 

 and filled. 



The experiments were made in two separate basins, whose supply of 

 water is kept absolutely separate, and whose levels differ 1 meter [3J 

 feet]. The first is a claire having an area of 50 square meters [about 

 538 square feet] and a depth of 90 centimeters [about 3 feet]. The sec- 

 ond is an old salt-pit, having an area of 11,000 square meters [nearly 2;^ 

 acres]. The water of the claire v: as partially renewed at every tide; 

 while the water of the salt-pit was renewed only by strong tides, and on 

 account of its large surface was continually agitated by a strong splash- 

 ing. The same kinds of collectors were i^laced in these basins. They 

 consisted of the shells of mussels and oysters, pieces of calcareous stones, 

 and potsherds. 



While these experiments were going on the saltness of the water 

 varied between 2.5° and 3.2°; it being naturally greater in the salt-pit, 

 where the water was rarely renewed, than in the claire where it was re- 

 newed nearly every day. 



Under conditions differing so much, both as regards the saltness of 

 the water and its renewal and agitation, the results obtained were iden- 

 tical. The spat attached itself in great quantities to the collectors, es- 

 pecially to those which presented a rough surface, such as the oyster- 

 shells, calcareous stones, and potsherds. Some fagots used as collectors 

 remained bare, which may perhaps be ascribed to the slow decomposition 

 of the wood in the closed water. Nevertheless the results were on the 

 whole very remarkable. On certain shells as many as 300 young oys- 

 ters could bo counted ; and if we take an average of GO to 80 per shell, 

 we are certainly below the actual facts. 



The following was the method ])ursued for obtaining embryos: We 

 took simultaneously or successively as reproducers: (1) Oysters from 

 the Government bed at Verdon, which the commissioner of marine at 

 Pauillac had sent us; (2) oysters originating at Arcachon, which had 

 been penned in our establishments for a year, and which never before 

 had shown any trace of rei)roduction. (These oysters are in a basin en- 

 tirely separated from the former.) The experiments succeeded equally 

 well in both cases, and the results were essentially the same, only the 

 Vertlon oysters appeared, as regards the maturity of their seminal liquids, 

 to be eight or ten days ahead of those from Arcachon. 



We threw the eggs and spermatozoa detatched from the seminal 

 glands into a large glass vessel containing 30 liters [about 8 gallons] of 



