192 



A. A. MERLIN ON THE SPERMATOZOON OF THE RAT. 



structure, which I have endeavoured to represent in the annexed 

 drawing, Fig. 1, made with a power of 2300 diameters (reduced 

 to 1650), obtained by means of a Zeiss' J apochromat of N.A. 

 1*4:26 and 27 compensating ocular. 



In the " head " the points noted and figured are : 

 1. A strongly stained portion of the endoplasm extending 

 from the fore to the middle part of the " head," situated close 

 to the concave under surface, and completely embedded /in, and 



Fig. 1. 



surrounded by, the gelatinous and homogeneous substance or 

 ectoplasm which constitutes the forward part. This endoplasm 

 exhibits near its tip an exceedingly small notch, or barb, which 

 is extremely difficult to define satisfactorily, and is indeed not 

 certainly visible in all specimens, although it has been traced in 

 a considerable number. A second and much more easily definable 

 notch exists a little farther from the tip, which not only cuts 

 into the endoplasm, but extends through the ectoplasm to the 

 convex upper edge of the organism. 



