268 ON SLAViisrA and ophidokais. 



Slavina appendiculata {VejdodsTcy). 

 Nais appendiculata, Z)' TTdehem. 



Segments 30-40. The dorsal bristles, except the first pair, short 

 and fine, more than two in each bundle ; the first pair very long, 

 each composed of three or more long setee. Corpuscles of peri- 

 visceral fluid oval and hyaline. One ring of touch-organs on 

 each segment. 



Slavina ltjeida. 

 Nais lurida, Timm. 

 Segments 30-40. The first pair of dorsal bristles long and 

 stout, not more than one long one in each bundle, sometimes a 

 second of half the length, which is also the length of the succeeding 

 ones, and of which there are not more than two in each bundle. 

 The touch-organs usually in two rings on each segment. Peri- 

 visceral corpuscles oval and hyaline. 



Sl/AVINA SEBPENTIlSrA. 



Oj)hidonais serpentina {Gervais). 

 Segments 70-80. Dorsal bristles short and straight, frequently 

 wanting. Touch-organs irregularly arranged on anterior seg- 

 ments, on posterior usually as in S. lurida. Perivisceral cor- 

 puscles spherical and granular. Usually four pigment-bands on 

 first five segments. 



BiBLIOGHlAPHT. 



D'Udekem. — Bull. Acad. Roy. Belg. (1855), xxii. p. 552 and plate. 



. Mem. Acad. Roy. Belg. (1859), xxxi. p. 21. 



Timm. — Arbeit. Zool.-zoot. Inst. Wiirzb. (1883), vi., pi. i. & ii. 

 Vejdovsky. — Thierische Organismen der Brunnenwasser von Prag, 



1882. _ _ - 



— — . System u. Morphologie der Oligochseten, 1885, p. 30. 

 Gruithuisen.— N. Act. Nov. Curios. (1828), xiv. p. 407 (Nais 



eschar OS a). 



DESCEIPTION OF PLATE XXXIII. 



Fig. 1. Slavina lurida. Ventral view, from life. X 90. 



2. S. appendiculata. After D'Udekem, Bull. Acad. Eoy. Belg. 1855. 



3. 8. appendiculata. After Vejdovsky, Syst.^u. Morph. pi. iii. fig. 17. 



4. Section of touch-organ. After Vejdovsky, I. c, pi. iii. fig. 21. 

 6. Slavina serjpentina. Side vievr, from life. X 100. 



