564 EMBEYOLOGY OF THE LOWER VERTEBRATES ch. 



objects. For laboratory purposes it is best to employ artificial 

 fertilization as in the case of the Sturgeon. 



Amia (Dean, 1896) spawns at Black Lake during the latter half 

 of April or May. The eggs are deposited on a compact site over 

 which the vegetation is pressed aside so as to form a clear space with 

 about a foot of water over it. The eggs, fertilized at the moment of 

 laying, adhere to roots or other portions of the water-plants. The 

 rate of development as in other cases varies greatly with the 



Fig. 249.— Stages in the development of Symbranchus. (After Taylor, 1914.) 

 o.r, optic rudiment ; P.F, pectoral fin rudiment. 



temperature and from four days to fourteen have been observed to 

 elapse between the deposition of the eggs and their hatching. 1 



Of Teleostei (Figs. 249 and 250) by far the most convenient for 

 systematic laboratory work are the Salmon (Salmo salar) and the 

 Trout (S. fario), eggs of which can be obtained in quantity from the 

 various hatcheries. The eggs obtained by " stripping " are fertilized 

 artificially and may then be sent by post packed in damp moss. 

 Small hatching boxes suitable for laboratory use can also be purchased. 2 



The eggs and larvae of marine Teleosts are often obtained in great 



1 Excellent developmental material of Lepidosteus and Amia may be obtained from 

 the Woods Hole Laboratory or from Mr. J. C. Stephenson, Washington University, 

 St. Louis. 



2 E.g. from the Solway Fisheries Co., Dumfries, Scotland. 



