564 EMBEYOLOGY OF THE LOWER VEKTEBRATES 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 halt' 

 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 



or 



o 



Fi<;. 249. Stages in the development of Symbranclnts. (After Taylor, 1914.) 

 o.r, optic rudiment : /'./'. pectoral tin 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- (X. fario), eggs of which can be obtained in quant iiy lmin the 

 \;irius hatcheries. The eggs obtained by " stripping " are fertili/ed 

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

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



Th.- eggs and larvae of marine Teleosts are often obtained in -real 



.-.lli-iit ili-vi-loj.mi-ntai mall-rial of AI' / // ( /I..\/, </.s ami Am\ ' m.iv !>< ol'taim-il from 

 tii.- Wood*. Ilolr l.al-oiaini v "i from Mr. J. C. Stcphenson, \\'a-luii--ton l!ni\ 



/;.,. !.., n, Bolwtj i Domfl Sootlmnd, 



