ULTRAVIOLET AND ARBACIA FERTILIZATION. 435 



ably adsorbed by the egg- surface to an extremely high degree, and 

 usually not enough of it is present in an active state in the spaces 

 between eggs to produce typical agglutinated masses of sperm, 

 when eggs are inseminated in fingerbowls in the laboratory. 



(c) Ultraviolet radiation produces a slight increase in the pTT 

 of egg- water. 



< /) Sperm suspensions become more translucent as a result of 

 radiation, in consequence of the formation of permanent irregular 

 aggregations of sperm which settle out of suspension. 



(g) The more concentrated suspensions of sperm show an in- 

 crease in viscosity and a decrease in surface tension following 

 radiation. The increase in viscositv is associated with the for- 



j 



mation of aggregates of sperm. 



(//) Radiated sperm undergo a reduction of agglutinability by 

 normal egg-water. The onset of agglutination is delayed, and the 

 duration of the phenomenon is shortened. 



(/) The more dilute suspensions are more susceptible to radia- 

 tion effects. 



(/) Radiation effects with eggs, egg-water, and sperm are 

 .graded by dosage of radiation. 



LITERATURE CITED. 

 Bartsch, O. 



'26 Uber Schaumbildungsfahigkeit und Oberflachenspannung. Kol- 



loid Zeitschr., Bd. 38, H 2, S. 177-1/9. 

 Clowes, G., and Bachman, E. 



'20 On a Volatile Sperm-stimulating Substance Derived from 

 Marine Eggs. Proc. Soc. Exp. Biol. and Med., Vol. 18, pp. 

 120-121. 

 Clowes, G., and Smith, H. 



'22 Relation of Hydrogen Ion Concentration to the Fertilization of 

 Marine Eggs. Jour. Biol. Chem., Vol. 50, Proc. XVI., p. xlix. 

 '23 The Influence of Hydrogen Ion Concentration on the Fertiliza- 

 tion and Growth of Certain Marine Eggs. Am. Jour. Physiol., 

 Vol. 64, pp. 144-159. 

 Glaser, O. 



'i4. A Qualitative Analysis of the Egg-secretions and Extracts of 



Arbacla and Astcrins. BIOL. BULL., Vol. 26, pp. 367-386. 

 'i4/> Autoparthenogenesis in Arhacia and Astcr'uis. BIOL. BULL., Vol. jf>, 



PP- 38/-409. 

 *2ii/ Note on the Pigment of Arbacia Secretion. BIOL. BULL.. Vol. 41, 



pp. 256-258. 

 '2i/> The Duality of Egg-secretion. Am. Nat., Vol. 55, pp. 368-373- 



