336 M. Treviranus on the Organized Bodies in 



nized parts of the seminal fluid, magnified three hundred times, 

 presented the following appearances : A drop of the secretion 

 of the testicle, diluted with water, was observed to contain 

 merely discs and vesicles. The discs were quite empty, and 

 the vesicles appeared like points. A drop of the secretion 

 found in the excretory duct of the testicle, when submitted to 

 the same process, presented very different phenomena ; it con- 

 tained only peduncles, which had separated from the discs, and 

 of which the ends were disengaged and bent back towards their 

 stems. On the other hand, in a wood-snail which I examined 

 on the 1st June, neither the secretion of the testicle, nor that 

 found in its excretory duct, contained any discs, but merely 

 peduncles and vesicles, the former only in the secretion of the 

 testicle, the latter in the secretion found in the excretory duct. 

 In other respects, both the fluids are white and opaque, and 

 the latter is generally thicker than the formei' ; but in this in- 

 stance the first was of a milky appearance, the latter clear and 

 semitransparent. The causes of these differences can depend 

 only on the circumstance that the discs separate from their pe- 

 duncles, sometimes at an earlier, sometimes at a later period, 

 and at one time expel the vesicles contained within them in the 

 testicle, at another time not until they have got into the excre- 

 tory duct. 



" In the sacculi of the dew-worm, which lie between the ova- 

 ries at their base, opening into the excretory ducts of the lat- 

 ter, and containing a thick yellowish secretion, I have also 

 discovered long filaments of this description, contracting into a 

 serpentine form when the secretion is mixed with water, and 

 resembling those met with in the Limax ater and Helix nemo- 

 ralis. In this animal also, they cover the inner surface of the 

 sacculi in layers, like tufts of hair. The seminal secretion, how- 

 ever, only contains globules of a smaller size unconnected with 

 the filaments, and which I have always found devoid of motion. 

 On the other hand, in the secretion of four sacculi which lie at 

 both sides of the ovaries, I observed very fine streaks and glo- 

 bules, in both of which lively and continued motions occurred 

 on adding water to the secretion. 



" In the medicinal leech (Hirudomedicinalis),and the horse- 

 leech (Hirudo gulo), the fructifying secretion is found in two or- 



