226 



ANNELIDA. 



Fig. 110. 



The penis itself (a) is frequently found protruded from the body after 

 death; it is a slender tubular filament, which communicates by its 

 origin with the contractile bulb (c), and, when retracted, is lodged in a 

 muscular sheath (>). The male apparatus is thus complete in all its 

 parts : the fecundating secretion derived from the double row of testes 

 is collected by the two vasa deferentia and lodged in the receptacles 

 (d d) ; it is thence conveyed into the muscular cavity (c) situated at the 

 root of the male organ of excitement, through which it is ultimately 

 ejected. 



(590.) The ovigerous or female sexual organs of the Leech are more 

 simple in their structure than those that constitute the male system. 

 They open externally by a small orifice situated immediately behind 

 the aperture from which the penis is protruded, the two openings 

 being separated by the intervention cf 

 about five of the ventral rings of the 

 body. The vulva, or external canal, 

 leads into a pear-shaped membranous 

 bag (fig. 110, g}, which is usually, 

 but improperly, named the uterus. 

 Appended to the bottom of this organ 

 is a convoluted canal (h), that com- 

 municates with two round whitish 

 bodies; these are the ovaria. The 

 germs which are formed in the ovarian 

 corpuscles, therefore, escape through 

 the tortuous duct (h) into the uterus 

 (</), where they are detained for some 

 time, prior to their ultimate expulsion 

 from the body. The exact nature of 

 the uterine sacculus, as it is called, is 

 imperfectly understood: some regard 

 it as a mere receptacle wherein the 

 seminal fluid of the male is received 

 and retained until the ova come in 

 contact with it as they pass out of the 

 body, and thus are subjected to its 

 vivifying influence ; other physiologists 

 believe that the germs escape from the 

 ovaria in a very immature condition, 

 and suppose that during their sojourn 

 in this cavity they attain to more com- 

 plete development before they are ripe 

 for exclusion ; while some writers go so far as to assert that leeches are 

 strictly viviparous, inasmuch as living young have been detected in the 

 interior of this viscus : but all these suppositions are easily reconcilable 



Generative apparatus of the Leech. 



