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prostomial glands (»Lippen(lrüsen" of the German authors) and 

 they resemble iu their microscopical structure more the salivary 

 glaiuis than the ordiuary glauds of the skin. 



Closely beneath the jaws the nervecollar is found, which con- 

 sists of a supra- and a suboesophageal pair of ganglia united 

 together. The suboesophageal pair is the first of a large number 

 of ganglia situated in the ventral part of the body. 



In niy figure I have represented the supraoesophageal ganglion 

 uuder the sectionned jaw; further are to be seen the suboeso- 

 phageal ganglion , one ganglion of the ventral chain and the 

 connectives, which unite the ventral ganglia. 



The uervous system is surrounded by a bloodsinus, in which 

 I have observed blood iu some of my sectious , but in my figure 

 the lumen is represented without blood. 



I have but little to say about the muscular system and I shall 

 mention here ouly what is of some importance for the place of 

 the unicellular glands in the body. The muscular fibres are ar- 

 ranged in the head especially in three directions. 



Near to the surface of the body beneath the epithelium small 

 groups of muscular fibres are fouud cut transversally. Those fibres 

 are situated close to the surface of the animal immediately under 

 the epithelium , but in the pharynx they are found at some di- 

 stance of the buccal wall. Those muscles are very strongly deve- 

 loped round the oesophagus and form a stout muscular mass, 

 undoubtedly of great importance to the mechanism of sucking. 

 Beneath those circular fibres are found the longitudinal ones; 

 they are well developed and form some layers. 



The ramifications of these muscular buudles into the sucker is 

 evident in my figure; their contraction shortens the body and 

 spreads out the sucker. 



Except the above mentioned muscular fibres, we meet every- 

 where radial ones , which prevent the extension of the folds of 

 the skin of the leech and perhaps widens the oesophagus at the 

 same time. 



Although these three groups of fibres form the raass of the 



