SPERMIOGENESIS OF THE PRIBILOF FUR SEAL 



485 



The mature spermatozoon 



Most of the following points were made out by the study of 

 smear preparations of the contents of the epididymis from mate- 

 rial which had been preserved in 3 per cent formaldehyde. The 

 preparations were stained in a large variety of ways, and studied 

 in water, in dilute glycerine and in balsam. 



The only descriptions of the spelrmatozoa of the Pinnipedia 

 thus far to be found in the literature are those given by Ballowitz 

 C08) for Phoca vituhna L., and by Retzius ('09 a) for Hahchaerus 

 grypus Fabr. In general form the spermatozoon of Callorhinus 

 is similar to those though differing in dimensions and in details. 

 The following table gives a comparison of the dimensions of 



TABLE 1 



the three forms. The figures for Phoca are taken from the 

 description of Ballowitz, while those of Halichaerus must be 

 regarded as approximate only, having been computed from the 

 plates of Retzius, he giving no exact measurements in figures of 

 this species. 



Caput. The head of the spermatozoon of Callorhinus alascanus 

 J. and C. (fig. 33) is of the form common among carnivora, being 

 oval in outhne, the anterior margin rounded, the posterior one 

 abruptly truncate and somewhat emarginate in the center. The 

 whole structure is flattened dorso-ventrally, one of its faces being 

 slightly more so than the other. In profile view it is lanceolate, 

 with an acuminate point (fig. 36). The head is covered by the 

 galea capitis, or head cap (fig. 33, h.c.,) the anterior margin of 

 which forms the cutting edge of the perforatorium. The head 



