124 H. H. NEWMAN. 



lerence is not nearly so obvious as is the case in the mouse egg. 

 Apart from the lack of typical tetrads in the second spindle the 

 chromosomes have the same general appearance as those of the 

 first. As an illustration of this similarity of chromosomes com- 

 pare Figs. 32 and 39, which are equatorial plate views of the 

 chromosomes of first and second polar spindles respectively. 

 The spindle shown in Fig. 41 differs from any other, either first 

 or second, that has come under my observation in that it appears 

 to have a set of mantle fibers in addition to the central spindle. 

 This, however, is not to be considered typical for second matura- 

 tion spindles in this species. 



All of the conditions thus far described have been found in 

 follicles of normal structure, in which there are no evidences of 

 follicular atresia, and are, therefore, to be considered as strictly 

 normal. 



X. THE SECOND POLAR BODY AND THE FEMALE PRONUCLEUS. 



My observations of the second polar body are limited to three 

 cases, the anomalous case described on the following page and 

 illustrated in Fig. 42; the normal case shown in Fig. 43; and the 

 fertilized egg, Fig. 44. The normal case from which the drawing 

 (Fig. 43) was made occurred in a follicle like that shown in 

 follicular stage n. The section cuts tangentially across one 

 part of the formative zone and just shaves a thin slice from the 

 deutoplasmic mass, shown in the form of coarse vacuoles. The 

 second polar body appears to be somewhat larger than the first, 

 in this respect resembling the egg shown in Fig. 42. The chromo- 

 somes of both polar bodies are well scattered and there are 

 evidences of an attempt at mitotic division. The female pro- 

 nucleus is in a condensed condition, but the individual chromo- 

 somes are distinguishable. Surrounding the mass of chromatin 

 is a capsule of homogeneous protoplasm, which probably insu- 

 lates the nucleus from its own cytoplasm. 



XI. AN ANOMALOUS CASE OF A THIRD POLAR SPINDLE. 



This case came to my attention very early in the investiga- 

 tion and was at first interpreted as a practically certain case of a 

 parthenogenetic first cleavage. In view of recent discoveries 



