32 THE ANJlTOMT OF THE LEECH. 



From the structure and position of the respective organs above 

 described, it certainly seems that we ought to reverse their supposed 

 offices ; instead, therefore, of describing the glandular bodies at present 

 considered testes, as such, it is much more reasonable to assign them 

 to the ovarian system and to consider the uterine sacs of Williams as 

 the male organs of generation. A few of the arguments which tend 

 to support such an opinion are that the spermatic fluid is invariably 

 projected from organs, while the germ fluid or ova are more silently 

 propelled along ducts or tubes. Again, Williams curiously enough 

 makes the following statement which is important: "It is here 

 essential to add that the ova are first produced in a stromatous layer 

 which constitutes one of the coats of the ovarian uterus, and that a 

 large number of them are contained in a common capsule until they 

 attain a certain degree of development, after which they may be 

 recognized near the outlet of the oviduct in a single and free state. 

 Ova are never found in the so-called respiratory saccules, but on the 

 contrary and invariably, a small quantity of sperm-fluid. Each of 

 these sacs is perforated at the point where it is attached to the integ- 

 ument by an orifice which opens directly externally. This vesicle 

 which from the date of the writings of Duges has been described as 

 ' the respiratory sac,' is a true vesicula seminalis ; it is designed to 

 receive the superfluous portion of the sperm secretion as it passes 

 from the testes to the ovarian uterus. Spermatozoa can always be 

 discovered in the vesicles." According to the above plan the sperm, 

 fluid must overflow the common duct and then pass by a second 

 lateral duct into the distaut and detached vesicula seminalis. Surely 

 there is no such complication in nature. On the contrary the follow- 

 ing is the simple and intelligible mode which she adopts : The bodies 

 described as testes are the ovaries, these open into the common duct ; 

 the structures designated ovarian-uteri are the testes with their 

 attached vesicula seminalis ; these bodies possessing, as shown by 

 Williams, irritable contractile walls, discharge the sperm-fluid into 

 the common duct and thus fertilize the germ-fluid. 



The office of the detached sac, said to be an uterus, and supposed by 

 Williams to be a mere arrangement for attaching individuals in copu- 

 lation, seems to be really more strictly a uterus, although on this 

 point more proof is needed. My reasons for inclining to the old 

 opinion is that during this last summer I twice found Leeches with a 

 circlet of young Leeches attached to the mouth of this curious sac, 

 and in a specimen presented to the Institute, not only are the 

 young ones shown so situated, but after the death, or more probably 

 in the death of the Leech, ova were extruded and now lie in the glass 



