1893.] NATURAL SCIENCES OF PHILADELPHIA. 281 



to a muscular coat of the sac itself. He mentions a " band " which 

 extends from the tuberosity of the ischium to the sac, but does 

 not state that it is muscular in character. He probably thought it 

 was not muscular since the term ' band ' is not used as one synony- 

 mous with fascicle. 



The point is one scai-cely worth noting were it not for the fact that 

 Hudson in his w 7 ork entitled " The Naturalist on the La Plata " 

 describes the act of expulsion of the fluid to be involuntary. It 

 would be possible for fluid to escape without control of the will, as 

 feces or urine might be voided involuntarily if the sac was endowed 

 with no musculature outside of its own walls. But it was held by 

 Dr. Allen as a conclusion drawn from his dissections that the semi- 

 tendinous muscle is an important factor in the act of expulsion, and 

 he believed it to be true that the demonstration proved, even if we 

 lacked evidence from the behavior of the animal at the time of 

 expelling the liquid, that the act is strictly voluntary. The semi- 

 tendinous muscle exhibits a constriction at its proximal third, from 

 which a muscular slip (as wide as the main muscle itself) arises. 

 The slip passes upward and backward to be inserted upon the sac of 

 the gland. 



The following was ordered to be printed : — 



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