150 Dr. A. Krohn on the Male Generative Organs o/Phalangium. 



of the body) there issues one of the above-mentioned narrow 

 canals, which may with perfect justice be characterized as vasa 

 efferentia (b b). In its forward course each of these canals 

 strikes first of all upon the origin of the tracheal stem of its side, 

 then bends inwards, and runs to the median line of the abdo- 

 men, where it meets with the canal of the opposite side, and 

 both pass into the origin of the vas deferens. Of the nature 

 of this long duct, which gradually increases in diameter, and is 

 chiefly rolled together into a close coil (c), Tulk has already 

 given a satisfactory account. I can completely confirm the 

 statement of this naturalist that the vas deferens, after passing 

 through the penis, opens at the extremity of the so-called glans*, 

 which is armed with a curved spine or hook at its apex, and is 

 moveably articulated upon the shaft of the penis. I may, how- 

 ever, remark that the vas deferens, after having become suddenly 

 and greatly dilated (d) just before its entrance into the penis, 

 appears so exceedingly narrow during its passage through 

 the latter, that the transverse section of its lumen bounded by 

 a chitinous coat only seems very slightly to exceed the diameter 

 of a single seminal corpusclef. 



The testis possesses a bounding membrane which passes into 

 the outer envelope of the efferent ducts; it is, however, not 

 hollow, but its mass consists throughout of round cells, fur- 

 nished with a distinct wall, and closely pressed together, which 

 contain a great number of small transparent vesicles. As a 

 nucleus, often surrounded by dark granules or molecules, makes 

 its appearance in these vesicles on the addition of acidulated 

 water, I regard them as the formative cells of the semen, whilst 

 the cells enclosing them seem to represent their mother cells. 



* This so-called glans no doubt functions as an excitant organ during 

 copulation. 



t The above-mentioned dilated portion of the vas deferens is distin- 

 guished from the preceding portions of this canal by a very thick chitinized 

 lining membrane and by a very strong muscular coat. From the great 

 narrowness of the duct in its passage through the penis, it might be sup- 

 posed that the dilated portion may act as an organ of propulsion in the 

 ejaculation of the semen. According to Tulk, the excitant organ (the so- 

 called glaua), which, during repose, is always bent back over the end of 

 the shaft of the penis, can be elevated or extended (that is, brought into 

 the same line with the shaft of the penis) by means of two muscles. I 

 must deny the existence of these muscles ; but, on the other hand, it is 

 not difficult to detect the presence of a single powerful muscle which is 

 evidently destined to this purpose. This muscle, which has hitherto been 

 overlooked, occupies half the length of the interior of the penis from the 

 base, and is connected with a strong sinew running straight to the excitant 

 organ, to the base of which it is attached. The mode of action of this 

 muscle may be easily ascertained by a simple experiment, namely, by laying 

 bare the sinew, inserting a fine needle into it, and pulling in the direction 

 of the traction of the muscle. 



