9go Sir E. Home's Additions to an Account 



of the vas deferens is analogous to the vesiculse seminales of 

 other animals, secreting its own fluid with which the semen 

 is to be mixed before it enters the penis, and the valvulae con- 

 niventes form a surface from which this secretion probably 

 takes place. 



It is deserving of observation, that the epididymis and vas 

 deferens were loaded with semen, which there is reason to 

 believe is not the case in quadrupeds, unless immediately pre- 

 vious to the act of copulation ; but in fishes, where the con- 

 nexion between the sexes is less complete, the semen appears 

 to be prepared at a more early period. 



The openings from the vasa deferentia are situated on each 

 side, four inches higher up than those of the ureters, rounded 

 in form, and kept closed by the pressure of two oviform liga- 

 mentous substances; these openings readily admit of dilatation, 

 so that the hand can pass into them. 



The penis has an infundibular form, and terminates by an 

 ■ oblique aperture about three inches in circumference. 



The holders correspond with those of the dog-fish, which 

 upon another occasion have been described to the Society ; the 

 spur bears a striking resemblance to that of the male orni- 

 thorhynchus paradoxus. There is a canal in each holder 

 communicating with a corresponding cavity between the skin 

 and muscles of the abdomen, eleven feet long and two wide. 

 The inner surface of this cavity is smooth, almost polished, 

 and of a beautiful white colour ; it contained a white mucus, 

 extremely viscid and tenacious. 



Opportunities of examining the brain of a fish of such 

 magnitude are of rare occurrence ; I have therefore not only 

 given drawings of the brain, (PL XIX, XX.) but also one 



