V1&'.--- 



,,.»^ 



Figure 283. — Photograph of the spawning male, C. virginica. The V cut in the left valve was made several weeks before 

 the experiment. Temperature 2.3.0° O. Sperm ejected through the opening of the promyal chamber is seen as a 

 white jet opposite the V cut. 



24° to 25° C. Many other substances including 

 various hormones (thyroxin, adrenalin, estrogen), 

 desiccated anterior and posterior pituitary, thy- 

 mus, thyroidin, cysteine, glutathione, peptone, 

 egg albumen, urea, different sugars (dextrose, 

 maltose, d-arabinose) , starch, and yeast stimulate 

 ejaculation in various degrees of effectiveness. 

 Suspension of desiccated thyroid gland (thyroidin) 

 in sea water was found to be the most effective 



stimulant, and it has been used in the Woods 

 Hole laboratory in preference to egg suspension or 

 egg water. 



Other substances may also provoke sexual 

 response. Miyazaki (19.38) found that the ex- 

 tracts from several algae, Ulva pertusa, Entero- 

 morpha sp. and Monostroma sp. induce spawning 

 in the males of C. gigas. 



Mature males (C virginica) respond also to live 



ORGANS OF REPRODUCTION 



311 



