216 



THE ORGANIZATION 



Fig. 127. 



Fig. 126. 



ages and gills so numerously repeated along the sides of the body 



of Myrianida, (fig. 43,) and the interior, 

 with the exception of the string of numer- 

 ous nervous ganglions, (fig. 126, g- 1 ,) pre- 

 sents a uniformity of organization scarcely 

 * inferior to that of Insects. When in its 



native habitat, a cavity in a rock on the 

 sea-shore, it extends its narrower anterior 

 end (hd) to an enormous length, as much 

 as eight times as long as the body, and expands the tip side- 

 ways, so as to give the whole proboscis the form of a very 

 high T with its right and left arms curled more or less back- 

 wards. 



The mouth (m) is not, as one would be apt to suppose, at the 



Fig. 126. Bonellia viridis. Rol. One half natural size. A diagramic view of 

 a marine worm, in a contracted state, hd, the proboscis ; m, the mouth ; st, the 

 stomach; i, the intestine; a, the posterior end of i; br*, the respiratory organs; 

 br, the point at which 6? -1 communicates with the intestine; A, the heart; A 1 , the 

 median dorsal vessel; A 2 , the same in the proboscis; A 4 , point of junction of A 2 

 with the lateral vessels (7* 3 , A 5 ) ; A 7 , point of union of A 5 , A 3 , under the stomach ; 

 A 8 , the vascular ring about ou 3 ; A 6 , A 9 , a small posterior vessel ; g, g 1 , g 3 , the ven- 

 tral nervous cord ; g~, the nervous collar which follows the path of the lateral 

 blood-vessels in the proboscis ; ov, the reproductive organ ; ov*, the matrix ; ot> 2 , 

 the outlet of oz? 1 ; ov 3 , the trumpet-shaped entrance to ov 1 . Compiled from the 

 illustrations of Lacaze Duthiers. 



Fig. 127. A diagramic end-view of fig. 126, from behind, t, the intestine; 

 fcr 1 , the respiratory organs ; br, point of junction of br 1 with i ; A, the heart ; 

 A 3 , lateral blood-vessels ; A 7 , inferior blood-vessel ; g, the ventral nervous cord ; 

 <7 2 , the upper commissure of the lateral branches (g*) of the nervous collar; oo l , 

 the matrix ; ow 2 , outlet of ov 1 ; g 1 , lateral branches of g. 



