148 NEREIS. 
The whole creature is white to the eye, unless a small portion about 
the head. 
It is restless and active, so as to render microscopical observations 
extremely difficult, and hence the crescent-shaped eye may consist of 
specks. 
One seemed to have grown somewhat large in two or three months. 
PuLaTE XX. 
Fic. 23. Nereis parva. 
24. Head, enlarged. 
25. Posterior extremity, enlarged. 
§ 6. Nerers Artes.—Ram’s Horn Nereis.—Plate XX. Figs. 5, 4, 5, 6. 
Length between two and three inches. Body composed of numerous 
segments, with a row of pencils on each side. Anterior extremity ter- 
minating in a stout projection, forked ; posterior extremity terminating 
in eight or nine stout prongs surrounding the vent. Two fleshy, recurving, 
flexible antennx almost constantly preserve a position resembling ram's 
horns. The general aspect of the animal is reddish ; a red vessel inter- 
nally traversing the body. 
It swims through the water by contortions, and its motions are 
sometimes so violent as to rend the body asunder. Also, it involves it- 
self in a knot, and forms a rude covering of sand. 
Pirate XXII. 
Fic. 3. Nereis aries, enlarged, from a specimen eighteen lines long. 
4. Anterior portion, upper surface, enlarged. 
5. Anterior under surface, enlarged. 
6. Posterior extremity, enlarged. 
§ 7. NEREIS REMEX, PHYLLODOCIA LAMINOSA.—Plate XXIII. Figs. 1, 2, 
9 a ow 
Oe; Oete 
This animal is one of the few which it seems impossible to recognize 
under the various nomenclature which has embroiled the genus Nereis. 
