, No. 3.] EGG OF ALLOLOBOPHORA FOETIDA. 609 



We should expect to find them formed at the expense of 

 some substance in the cell, as they are not constant structures 

 and appear to be a pathological feature. In photo. 10 we have 

 an exaggerated expression of the phenomenon (an unusual 

 number of granules), this aiding us in interpreting their 

 origin. This photograph indicates that they have arisen at 

 the expense of the head of the sperm itself. Less than 

 half of the length of the head is shown in this section ; but a 

 comparison of its diameter with that shown in photo. 2 indi- 

 cates a great loss of substance. 



In photo. 1 1 we see a part of a contracted head of a sperm 

 which appears to have been fixed in the act of constricting off 

 a sperm granule.^ 



Early Stages of Development of the Pronjiclei. 



The photographs of Plate XXXVII illustrate the early 

 stages of development of the male and female pronuclei — 

 four fixatives being represented. 



Photo. 23 shows a transverse view through the second matu- 

 ration spindle, which has reached the anaphase of development. 

 These are the chromosomes approaching the inner pole of the 

 spindle, and which are destined to form the female pronucleus. 

 There are eleven chromosomes in the first and second spindles, 

 and in this photo, each one of the eleven is shown. This 

 photo, was taken by Dr. Fuller, from a slightly crushed oocyte 

 second order. 



Photo. 24 shows a little later stage of development (telo- 

 phase). This section contains five or six of the chromosomes, 



1 In the Journ. of Morph., vol. xvi, No. i, 1899, Byrnes describes small round 

 bodies often accompanying the sperm-nucleus in Limax agrestis, and says they 

 may owe their origin — although she does not illustrate this point — to particles 

 of chromatin constricted off from the sperm-nucleus before it becomes vesicular, 

 having seen a " few cases in which a portion of the chromatin seemed to be in 

 process of constricting from the sperm head." As she does not suggest they are 

 a pathological expression, on the contrary implying they have a function, it is a 

 question whether they are the same structures we show in photos. 1 1 and 12. We 

 regret the necessity of mentioning Miss Byrnes's paper in a footnote. The number 

 of the journal in which it appeared was issued in June, 1900, and her paper was 

 not read until just before the receipt of our final proofs. 



