232 C. O. WHITMAN. 



I think, that this course of events was the result of non- 

 fecundation.^ 



The Pellucid Spot. — The polar figure, the outward expression 

 of the radial hues of one pole of the aniphiaster, becomes larger 

 and more sharply defined j and at the end of 10 — 25 minutes 

 after deposit, a minute pellucid spot appears exactly in its centre. 

 This spot is entirely free from yolk-spheres and granules, but 

 appears dark on account of the opacjue background. It increases 

 in size and at the end of about 30 minutes after deposit, mea- 

 sures 0-03 mm. to O'Oi mm. (diam.). This spot is the central 

 part of the polar area of the outer star, which is so deeply co- 

 loured with carmine in my preparations {'^'^^. 62, G3, cp). 



This was found by Robin ("espace clair circulaire") in the 

 egg of IMephehs, but overlooked in the case of Clepsine ( VV)* 



(c) Polar Grlobules (figs. 1 — 7). — An interesting phenomenon, 

 overlooked by all my predecessors, accompanies the appearance 

 of the polar globules (" Richtungsbliischen "). Robin gives a 

 very detailed account of the appearance of these globules, and it 

 is therefore all the more surprising to find that he failed to see 

 the most conspicuous part of the whole process. 



Thirty minutes^ after deposit the egg passes, from the oval- 

 elliptical form of fig. 1, PI. XII, into the biscuit form of fig. 2. 



The first time I saw this, I supposed the egg was in process of 

 cleavage. But the constriction in this case does not extend 

 much dee})er than in fig. 2, and passes gradually from the middle 

 towards the end which shows the pellucid spot and the polar 

 figure. The constriction is|perfectly regular and continuous in 

 its movement towards one pole of the egg. 



In 10 — 15 (45 min.) it is completed, leaving only a nipple- 

 like protuberance, from which the first polar globule begins to 

 project. That part of the polar globule first to appear is per- 

 fectly transparent, but the half last eliminated is filled with 

 minute, highly refractive granules, the outer border of which 

 forms a straight line at first. At the completion of the elimina- 

 tion (50 min.) the egg is flattened at this end, and slightly 

 depressed just under the jxdar globule. The yolk at this time is 

 removed from the vitelline membrane by considerably more than 

 the diameter of the polar globule. This space, filled with a 

 fluid (perivitelline tluid) which is a little less traTisparent than 



' Colasanti (127) has just published some interesting observations on the 

 duration of tlie q^uicsccnt 5^«^ej['' LebensdauerJ') of the unincubated hen's 

 egg. Tlic average ITnie during wfiicli this condition may be maintained, 

 without fatal injury, is estimated at three weeks, in very rare cases at four 

 weeks. 



' The time will be stated accordin2: to the average of a few accurately 

 noted cases. DilTcrent cnses vary much. Time elapsed siuce deposit will 

 liercafier be placed in [)arenliiesis. 



