760 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [20] 



111 conclusion I have to express my indebtedness to Dr. Brooks for 

 the assistance afforded me at Beaufort, not only in conducting the ex- 

 periments, but in permitting me to use the steam-launch and employes 

 attached to the Johns Hopkins Laboratory. I am also under great obli- 

 gations to Mr. H. C. Eowe, of Fair Haven, Conn., who allowed the use 

 of his ofQce and part of his packing-house as a temporary laboratory, 

 supplied me with all the oysters I used, and j)ut his steamers at my 

 service whenever I desired to employ them. I am also indebted to him 

 for making my stay at Fair Haven as agreeable as possible, and giving 

 me all the information in his power regarding the Connecticut oyster 

 fisheries. 



EXPLANATION OF THE PLATE. 



Fig. 1. Method of arranging plates so as to separate sicimming embryos 

 from dead eggs. — B is the lower dish, containing oyster shells or carbon- 

 ate of lime. A is the plate holding eggs in jirocess of segmentation. 

 Plate A is slightly inclined and nearly full of water. When the em- 

 bryos begin to swim, a minute supply of water is added to A from the 

 jar C, by means of a siphon, D. The supply is so arranged that the 

 drops strike the edge of the plate A, so as to prevent any disturbance 

 of the eggs in the bottom of the plate. Water from A will overflow in- 

 to B drop by drop, carrying the swimming embryos with it. A piece 

 of paper or card-board {x) should be placed so as to prevent any con- 

 siderable fall from A to B. 



Fig. 2. Metfiod with funnel. — The figure explains itself sufficiently, B 

 reiiresenting the funnel and A the jar which is to contain the embryos. 

 The only point of importance is the necessity of giving the funnel B a 

 slight inclination so that the overflow may be more constant and in one 

 place. 



Fig. 3. — B shows the character of funnel used during the past season, 

 X being the cork with perforation for glass tube s, through which the 

 jet of air or water was forced. The disadvantage of the arrangement 

 consisted in the form of the funnel. The eggs collected in a thick layer 

 on and around the cork, as shown by the shaded parts in the figure; in 

 the middle, the jet kept the majority in suspension. The improved 

 cone or funnel shown in Fig. 4 would, I think, obviate to a great extent 

 this evil, the interior of the funnel being perfectly conical and the tube 

 of rubber conveying the air or water fitting over the apex of the ex- 

 terior. The channel yz should be very small, as only a minute jet of 

 either air or water is necessary or desirable. 



Fig. 5 shows an air pump devised by Brooks, which is a convenient 

 arrangement for the use of laboratories situated where there is no great 

 head of water attainable. B is a tube, with funnel at the top (c) in- 



W. and S. E. from that point. (The usual set of the tide is in that direction.) While 

 the foregoing are favorable indications, they are not considered sufficiently strong to 

 justify an assertion that the experiment was entirely successful. Other attempts may 

 settle the question. 



