156 BOARD OF AGRICULTURE. 



The spermatozoon differs in aspect in various animals. In 

 man it is a perfectly clear, hyaloid, filamentous body, in which 

 a dilated portion called the head may be observed, from which 

 is prolonged a tail or filament, which generally tapers to an 

 extremity hardly visible from its tenuity. The head, or 

 larger extremity, is flattened from side to side, and of a con- 

 ical form, the pointed extremity being anterior. The sper- 

 matic filament of the bull is somewhat similar, but the blunt 

 portion of the oval is anterior, and there is a tendency to 

 exhibit a darker anterior and a clearer posterior portion. In 

 the rat and mouse the head or body of the filament is unsym- 

 metrical and curved. In the common cock the heads are 

 oblong and considerably elongated ; in the common sparrow, 

 wavy. In the common perch the spermatozoa exhibit a 

 rounded head ; in the river crawfish the filaments radiate 

 from the circular head, and are numerous. 



When the spermatozoa have escaped from the male pas- 

 sages their active movements commence, and, by the continu- 

 ous vibratory or other movement of the filamentous tail, they 

 are propelled forward. The tail alone has the power of move- 

 ment, and it wisps about with an energy sufficient to move 

 many times the weight of the spermatozoon. In the interior 

 of the female organs of generation these movements are con- 

 tinued for a longer period than in any other situation. In 

 the queen bee the capacity for movement is retained for sev- 

 eral months after they have been discharged by the drone 

 bee ; and in the mammalia the movement may continue for 

 several days after copulation. Leuwenhock points out that 

 the spermatozoa of the dog will live or retain their movements 

 for more than seven days preserved in a glass tube ; and Dr. 

 Percy, of New York, reports a case where living spermatozoa 

 issued from the os uteri of a female eight and a half days after 

 the last sexual connection. In a bat that had been isolated 

 for thirty-six hours, both the vagina and uterus were filled 

 with spermatozoa in lively movement. 



Even this full development does not, in all cases, seem 

 necessary for the fulfilment of the function of the spermatic 

 filament. In certain animals, such as the decapod Crustacea 

 and others, the spermatic elements are cast forth by the male, 

 and are transferred to the organs of the female while they are 



