608 



ANNUAL EEPORT SMITHSONIAN INSTITUTION, 190S. 



observation of Dr. Ulric Dahlgren, 

 an individual may exclude two egg 

 rafts at the same time. 



The egg raft, after full expan- 

 sion in the water, is a soft jelly- 

 like mass, quivering to the touch, 

 but withal rather tenacious and 3 

 or 4 feet long by 2 to 4 inches 

 or thereabouts in breadth, moder- 

 ately uniform in the width, and 

 tapering abruptly and blunt at 

 the extremities. It is also rather 

 thick, with blunt edges. The en- 

 tire mass is thickly permeated with 

 eggs, which appear to be in several 

 irregular layers, or at least more 

 than one. After some days, and 

 when the eggs have matured, the 

 jelly probably dissolves and em- 

 bryos are apparently thus liber- 

 ated, but exact observation is neces- 

 sary to confirm (or disprove) this 

 supposition. The eggs are innu- 

 merable and each one, wdien fresh, 

 about a millimeter in diameter, but 

 according to Gudger, " after hav- 

 ing been in a formalin solution 

 measured not much more than 

 half (O.GO) of a millimeter in di- 

 ameter." 



Also, according to Gudger, 

 " there are no oil drops visible in 

 the living eggs of Pterophryne," 

 but, " in sections, some eggs show 

 a small number of minute vacuoles 

 indiscriminately scattered under 

 the germ disk and around the cir- 

 cumference of the yolk. Some are 

 devoid of these." 



All of the many Pterophrynes 

 that have been found in the sar- 

 gassum drifted on the American 

 Fig. 44.— Raft with eggs of a ptero- coasts liave been females, or at 

 fr^orDr.^Hugh'''smkh! "" ^^°'°^'^^^' least none has been recognized as 



