XL REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



but the conditions are quite different in the case of these species. The 

 shad and alowife have non-adhesive eggs (those of the hitter slightly so 

 at first), and are hatched out in warm water, or with a rising tempera- 

 ture. The egg of the herring, on the other hand, is adhesive, and is 

 hatched at a low and descending temperature, the difference in physical 

 conditions demanding different treatment, the nature of which the pro- 

 posed experiments will no doubt settle satisfactorily. In Dr. Meyer's 

 apparatus glass plates are arranged horizontally with the eggs on the 

 nnder side, a condition impossible in the case of the ale wife. 



The Carp. — (Ci/prinus carpio.) 



The Druid Rill Park Station. — I have already referred in previous re- 

 ports to the various experiments of the Commission looking to the intro- 

 duction into the United States of the best varieties of the German carp, 

 a species considered to be of very great utility, especially to the South, 

 for food purposes, and bidding fair to stand in the same relation to the 

 farmer among fishes that domestic fowl do among birds. The fish brought 

 in by Mr. Hessel in 1877 were cared for at the Druid Hill Park, under 

 the direction of Mr. T. B. Ferguson, commissioner of fisheries of the 

 State of Maryland, and by permission of the i^ark authorities. It was 

 considered ad visablej however, to have a portion of the supply in Wash- 

 ington, where the fish could be more immediately under supervision. 

 Inquiry was therefore made as to a suitable location for the fish, either 

 in ponds already built, or to be constructed. It was, of course, thought 

 best that they should be placed on government ground, where there 

 would be no question as to rental. Several small lakes on the Soldiers' 

 Home property were at first thought of, but the governors were unwill- 

 ing to allow the changes necessary to fit them for the purpose, and it 

 was with difficulty that suitable ground could be found for the construc- 

 tion of new receptacles. The work was under the direction of Mr. Hes- 

 sel, who had a survey made, and laid out the contour. Soon after the 

 work was begun, it was ascertained that the supply of water that had 

 been relied upon for this purpose was inadequate, and the enterprise 

 was abandoned. In this emergency Mr. Hessel had his attention called 

 to the so-called "Babcock Lakes," two in number, which have a surface 

 of about G acres each, situated on the Monument Lot, and separated by 

 a driveway. These were found suitable in every way as to size, supply 

 of water, &c. Application was made to Congress, at its special session, 

 for the privilege of using these ponds, and for an appropriation to adapt 

 them to the required service. The application was granted, and $5,000 

 allowed to put them in order. The work was conducted by Colonel 

 Casey, with all due economy, the plans being furnished by Mr. Hessel. 

 The ponds were drawn off and graded, so that a series of ditches, radiating 

 from one point, would concentrate therein the contents of the pond. A 

 basin or collector was built at this outlet, walled with brick and armed 

 with heavy plank, and a suitable gateway and overflow was established. 



