48 GUSTAF EISEN, ON THE AECTIC OLIGOCH^ETA. 



Fig. 23. Neoenchytrceus durus n. sp. 

 a = the worm, nat. size. 

 b = the front part, seen from the side. 

 c = the hind part, seen from the side. 



d = a bundle of spines showing their relative size and form. 

 e = a single spine still fnrther magnified. 

 / = the front part of the nervous system. 



g = the supra-cesophagial ganglion from another individual, showing a slight variation in form. 

 h = the receptacle furnished with a single aecessory gland at the base. 

 k = one of the ovaries with numerous ripe eggs. 

 m = a floating ovary with a single ripe egg. 



1, = an ovary with ripe and unripe eggs in different stages of developmeut. 

 n = another ovary with two ripe eggs fixed by several muscles to the body-wall. 

 p = another ovary. 



q = perigastric cells without cell contents. 



r = a perigastric cell of another kind with nucleus and cell-contents. 

 s = the efferent duct and penis. 



PLATE XIII. 



Figs. 24 to 32 represent the segmental organs of the following species: 

 Fig. 24 = Mesenchy tresus primcevus n. sp. 



» 25 = » mirabilis n. sp. 



» 26 = » falciformis n. sp. 



» 27 = Archienchytrmus Levinseni u. sp. 



» 28 = » tenellus n. sp. 



» 29 = » lampas n. sp. 



» 30 = » Dichsoni n. sp. 



» 31 = » g emmatus n. sp. 



» 32 = » ochraceus n. sp. 



PLATE XIV. 



Fig s - 33 to 41 represent the segmental organs of the following species: 

 Fig. 33 = Archienchytrmus nasutus n. sp. 

 » 34 = » profugus n. sp. 



« 35 = Neoenchytrceus fenestratus n. sp. 

 » Vejdovskyi n. sp. 



» Stuwbergi n. sp. 



» hyalinus n. sp. 



» callosus n. sp. 



» Ratzeli Ei sen. 



» durus n. sp. 



PLATE XV. 



Figs. 42 to 66 represent diagrammatic figures of the organs of generation of different species. The num- 

 bers affixed ind^cate the segments and t = testidés ; o = ovaries ; ef = efferent duct; rs = receptacle. 

 Fig. 42 = Mesenchytrmus primcevus n. sp. 

 » 43 = » mirabilis with five pair of testicles. 



» 44 = » mirabilis with three pair of testicles. 



» 45 = » mirabilis with only one pair of testicles. 



» 46 = » falciformis n. sp. 



» 



36 = 



)> 



37 = 



» 



38 = 



» 



39 = 



» 



40 = 



» 



41 = 



