ANNULATA. 



229 



ChcBtogaster V. BAER. Eyes none. Fasciculi of set ventral, 

 ings slightly distinct. 



Sp. Ckcetogaster limncei V. BAER, Nov. Act. Acad. Gees. L. C. Nat. Curios. 

 Vol. xm. PL i, pp. 611615, Tab. XXIX. fig. 23; DUGES Ann. des Sc. 

 nat. sec. Se'r. vni. Zool. PL i, f. 24. 



jEolosoma EHRENB. Eyes none. Body distinctly articulate ; 

 iteral fasciculi of setae in each joint. Mouth anterior inferior sur- 

 lounted by a lip dilated, produced. 



Sp. JSolosoma Hemprichii EHRENB. Symb. phys. Phytozoa, Tab. v. fig. i. 



Pristina EHRENB. Eyes none. Upper lip produced into a soft 

 earded proboscis. Setae lateral. 



Sp. Pristina longiseta EHRENB. Symb. physic, evertebr. Dec. I. &c. 



Nals MUELL. (exclus. sev. spec.) Eyes two. Setae lateral, long: 

 asciculi of short setse on the belly. 



Sub-gen. Stylaria LAM. Proboscis frontal, styliform, soft. 



Sp. Nais proboscidea, Nereis lacustris L., TREMBLEY M&m. sur les Polyps, 

 PI. 6, fig. i, (Millepied a dard) ; KOES. Ins. in. Tab. 78, figs. 15 a, 

 1 6, 17, 1 8, g, h, i, Ic; Tab. 79, fig. i ; MUELLER Naturgesch. einiger 

 Wurmarten, s. 14 73, Tab. i; GRUITHUISEN Nov. Act. Acad. Leop. Car. 

 Natur. Curios. Tom. xi. pp. 233 248, Tab. xxxv. 



Sub-gen. Ndis LAM. Proboscis none. 



Sp. Na : is serpentina GMEL., EOES. Ins. in. Tab. xcn. ; MUELLER Naturgesch. 

 einiger Wurmarten, s. 84, Tab. IV. &c. 



On the propagation of Na'is see B. LEUCKART Ungeschlechtliche Vermehrung 

 lei Nats proboscidea, Archivfur Naturgesch. 1851. SCHULTZE on the same 

 subject, ibid. 1852, s. 3 7. 



The genera noted above form a small natural group of worms, for 

 the most part living in fresh-water, the Naidina of EHRENBERG. 

 Comp. on these and some other genera P. GERVAIS, Note sur la 

 disposition systematique des Annelides chetopodes de la famille de 

 Na'is, Bullet, de VAcad. r. de Bruxelles, Tom. v. no. 1 ; O. SCHMIDT 

 Beitrdge zur Anat. u. Physiol. der Na'iden; MUELLER' sArchiv. 1846, 

 s. 406, &c. Besides the propagation by eggs, these animals are also 

 multiplied by spontaneous division. The most complete observations 

 on this point relate to Na'is proboscidea. In the last joint of a 

 simple Na'is (which MUELLER calls Jung-fer Na'id, Virgin Na'is) a 

 young Na'is with eye-spots is gradually developed; it grows and 

 remains connected with the mother : sometimes on this a second or 



