ABRANCHIATE. 465 



Nais; Lin. 



The Naides have an elongated body, the rings of which are less 

 distinct than in the Lumbrici. They inhabit holes made by them 

 in the ooze, from which one half of their body projects and is con- 

 stantly in motion. Black points are observed on the head of some 

 of them, which may be taken for eyes. They are small worms, 

 whose power of reproduction is as astonishing as that of the Hydras. 

 Several species are found in the rivers, Sec. of France. 



Some of them have long set3e(l), 



And sometimes a long proboscis before(2), 



Or several small tentacula at the posterior extremity(3). 



Others have very short set3e(4). 



Certain Annelides, hitherto referred to the Lumbrici, which con- 

 struct tubes of clay, &c., in which they live, might be approximated 

 to this genus(5). 



Clymena, Sav. 



The Clymense also appear to belong to this family. Their thick 

 body has but few rings, which are mostly furnished with stout setae; 

 a little higher, and near the back, is a bundle of finer ones. There 

 are neither tentacula nor appendages to the head. Their posterior 

 extremity is truncated and radiated. They inhabit tubes(6). 



(1) Na'i's elinguis. Mull., Wurm., II; — N. littoralis. Id., Zool.. Dan., Ixxx. 



(2) Na'is proboscidea. Id., Wurm., I, 1 — 4, of which Lamarck makes his genus 

 Stylaria. 



(3) Na'is digitata, Gm., cxca. Mull., lb., V, the genus Pkoto, Oken. 



(4) iVaVs i)ermicu/am, Gm., Rses., Ill, xciii, 1 — 7; — N. serpentina. Id., xciii. 

 Mull., IV, 2 — 4; — Lumhricus turbifex, Gm., Bonnet., Vers d'eau douce. III, 9, 10, 

 Mull., Zool. Dan., Ixxxiv; — Lumhricus lineatus, Mull., Wurm., Ill, 4 — 5. 



(5) Lumhricus tuhicola. Mull., Zool. Dan., Ixxv; — Lumh. sahellaris, lb., civ, 5. 

 M. Lamarck unites them with the Na'is tuhifex, and makes it his genus Tubifex; 

 it requires, however, a new examination. 



(6) Clymena amphistoma, Sav., Eg., Annel., pi. i, f. ; — CI. lumbricalis, Ott. 

 Fabr., Aud. and Edw., Litt.,de la France, Annel, pi. x, f. 1 — 6; — CI. Ebiensis, 

 Aud., and Edw., lb., f. 8—12. 



Vol. II.— 3 I 



