146 NEREIS. 



3. NEREIS (NEPHTYS) LINEATA, NEPHTYS MARGARITACEA. Plate XXI. 

 Figs. 4, 5, 6, 7, 8, 9, 10. 



Length ten inches, form round : the body divided into numerous 

 segments, bounded by a row of pencils on each side.* Two short stumps 

 are on the head ; and a proboscis of extraordinary dimensions is occasion- 

 ally darted forth. Sometimes a black speck is seen in front, but it is 

 neither constant, nor are eyes visible. The figure of the proboscis varies 

 considerably according to the specimen. That of a large Nereis, being 

 somewhat barrel-shaped, extending three-quarters of an inch, by half an 

 inch wide in the middle, beset by several rows of spinous short papilla? 

 towards the extremity, which is terminated by a circle of them. The 

 largest row is composed of at least thirty. The proboscis, as if a hard 

 substance, which it is not, reflects the light. It is protruded in the ex- 

 treme weakness of the animal, which it at length seems incapable of 

 withdrawing. 



This species swims by a serpentine motion, in a horizontal direction, 

 with great violence and rapidity. When at rest it lies among sand, close 

 to the bottom of its vessel, with partial protrusion of the head. It is 

 extremely timid, and if above, retreats downwards on the slightest alarm. 

 If its site be about to become dry, the body twists, as if preparing to 

 leap. Colour white, with a line down the middle. 



This animal dwells among the sands of the sea- shore, somewhat 

 lower than at half-tide. 



PLATE XXI. 



FIG. 4. Nereis (nephtys) lineata, adult. 



5. Small specimen, taken at Blackness Castle in 1809, coiled 



' L The same, extended. 

 5. B. | 



6. Anterior extremity of fig. 4, enlarged. 



7. Anterior extremity of a smaller specimen (fig. 5), enlarged. 



* Dr Johnson ennumerates 143 segments in two specimens. Ann. and Mag. of Nat. 

 Hist. v. viii. p. 341. 



