MALE ACCESSORY REPRODUCTIVE ORGANS 261 



are innervated exclusively from the lumbar nerves, as above 

 described.^ 



In view of the facts which have been related, it would appear 

 that ejaculation is a reflex act of some complexity involving 



III. 



IV. 



Fig. 66. — Diagram illustrating innervation of internal genital organs of 

 male oat. (From Nagel. ) 



H., hypogastric nerve; Ur., ureter; V. D., vas deferens ; II. III. IV., 

 branches arising from 2ud, 3rd, and 4th lumbar nerves. 



more than one centre in the spinal cord. The centre for the 

 final expulsion of the semen must be the same as that for erec- 

 tion, since the muscular mechanisms concerned are to a large 

 extent identical in each case. The centre presiding over the 

 internal generative organs is apparently in the lumbar spinal 



' Langley and Anderson, toe. cit. 



