GNATHOBDELLIM; 481 



The NERVOUS SYSTEM exhibits the typical structure of other segmented worms ; 

 the sensory organs consist of the previously mentioned goblet-shaped cutaneous 

 sensory organs, of the organs of taste, and of eyes, the latter frequently being 

 present in large numbers. 



The EXCRETORY or segmental organs exhibit many peculiarities, which cannot, 

 however, be detailed here. They commence with funnels in the lacunes of the body 

 cavity, and usually discharge on the ventral surface. 



Almost all the Hirudinea are hermaphrodite and copulate reciprocally. The 

 two ovaries are very small, and the oviducts that proceed from them soon unite into 

 a common duct, which then passes into the uterus and discharges through the 

 short vagina in the median line of the ventral surface behind the male, organs into 

 the so-called clitellar region. The male sexual apparatus consists of symmetrically 

 arranged testicles, varying in number according to the species, the short vasa 

 efferentia of which, one by one, run into the vas deferens, passing towards the front 

 on each side. In front, at about the level, or a little in front, of the female, ge,nitalia, 

 the two vessels pass into a convoluted mass of tubes to the so-called epididymis, and 

 then discharge into the single protractile penis (fig. 3480). 



All leeches deposit so-called COCOONS. These are small barrel-shaped or pouch- 

 like bodies, which are surrounded by a thicker shell and contain a number of eggs 

 in a large mass of albumen ; the albumen originates from glands of the generative 

 organs, the shell substance from cutaneous glands of the clitellar region. 



Family. Gnathobdellidae (Leeches with Jaws). 



These are distinguished by the possession of usually three jaws in the pharynx; 

 the body consists of twenty-six segments. The posterior sucker is large and flat; 

 the anterior sucker is smalleiv The Hirudinea have five pairs of eyes, the Nephelintz 

 have four pairs. 



Genus. Hirudo, L., 1758. 



The entire body consists of 102 annulations, five appearing on one segment in 

 the central region of the body. The pharynx has three semicircular jaws, the arched 

 border of which is beset with numerous teeth (50 to 100). The male sexual orifice 

 lies between the thirtieth and thirty-first rings, the female orifice between the thirty - 

 fifth and thirty-sixth. There are numerous species, some of which are utilized for 

 medicinal purposes. 



Hirudo medicinalis, L., 1758. 



It occurs in numerous colour varieties, one of which has been designated 

 Hirudo officinalis, Moq.-Tandon. Usually the dorsal surface is greyish-green 

 and is 'marked with six rusty-red longitudinal 

 stripes. The ventral surface is olive-green, more 

 or less spotted with black, and marked at the 

 sides with a black longitudinal line. The length / 

 averages 8 to 12 to 20 cm. This leech lives in 

 swamps, ponds and brooks, overgrown with plants 

 and having a muddy bed. The cocoons are 

 deposited in the soil at the sides. Europe, as 

 well as North Africa, is its home. At the present 

 day it has been exterminated from most parts of 

 Central Europe, but it is still very common in 

 Hungary. Its use for medicinal purposes is well FIG. 348E. Hirudo medidn- 

 known. A large leech can suck about 15 grs. of alfs - , * ^terior e nd with 



. . y f . open buccal cauity, with the jaws, 

 blood, and about the same amount is lost through f at t h e; ^ ^ e j aw isolated. 



secondary haemorrhage. (After Glaus ) 



