ANNULATA. 229 
.Chetogaster V. BAzR. Eyes none. Fasciculi of sete ventral. 
Rings slightly distinct. 
Sp. Chetogaster limnei V. Barr, Nov. Act. Acad. Ces. L. C. Nat. Curios. 
Vol. xu. Pl. 2, pp. 611—615, Tab. xx1x. fig. 23; DueEs Ann. des Sc. 
nat. sec. Sér. vit. Zool. Pl. 1, f. 24. 
Afolosoma EXHRENB. [Eyes none. Body distinctly articulate ; 
" lateral fasciculi of setee in each joint. Mouth anterior inferior sur- 
mounted by a lip dilated, produced. 
Sp. Molosoma Hemprichiti EHRENB. Symb. phys. Phytozoa, Tab. v. fig. 2. 
Pristina EnRENB. Eyes none. Upper lip produced into a soft 
bearded proboscis. Setee lateral. 
Sp. Pristina longiseta EHRENB. Symb. physic. evertebr. Dec. 1. &e. 
Nais Muctt. (exclus. sev. spec.) Eyes two. Sete lateral, long: 
fasciculi of short sete on the belly. 
Sub-gen. Stylaria Lam. Proboscis frontal, styliform, soft. 
Sp. ais proboscidea, Nereis lacustris L., TREMBLEY Mém. sur les Polyps, 
Pl. 6, fig. 1, (Millepied a dard); Roxs. Ins. ut. Tab. 78, figs. 15 a, 
16, 17, 18, g, h, i, k; Tab. 79, fig. 1; MuxELLER Naturgesch. einiger 
Wurmarten, 8. 14—73, Tab. 1; GRUITHUISEN Nov. Act. Acad. Leop. Car. 
Natur. Curios. Tom. XI. pp. 233—248, Tab. Xxxv. 
Sub-gen. Nais Lam. Proboscis none. 
Sp. ais serpentina Guet., Roxs, Ins. 11. Tab. xcrr.; MuELter Naturgesch. 
einiger Wurmarten, s. 84, Tab. tv. &e. 
On the propagation of Nats see R. LEuckart Ungeschlechtliche Vermehrung 
bei Nais proboscidea, Archiv fiir Naturgesch. 1851. ScHULTZE on the same 
subject, zbid. 1852, s. 3—7. 
The genera noted above form a small natural group of worms, for 
the most part living in fresh-water, the Vaidina of EuRrEnBerc. 
Comp. on these and some other genera P. Gervais, Vote sur la 
disposition systématique des Annélides chétopodes de la famille de 
Nais, Bullet. de 0Acad. r. de Bruxelles, Tom. v. no. 1; O. Scumipt 
Beitrdge zur Anat. u. Physiol. der Naiden ; Murwurr’s Archiv. 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 Nais proboscidea. In the last joint of a 
simple Nais (which Murttsr calls Jungfer Naid, Virgin Nais) a 
young Nais with eye-spots is gradually developed; it grows and 
remains connected with the mother: sometimes on this a second or 
