66 THE MICROSCOPE. Mcay 



twelfth on each side, where they disappear. These balls 

 are placed on, the inner or upper face of the filament-stem, 

 at the point where the pectination ceases, the stem itself 

 being continued to a slender point beyond it, and consti- 

 tuting the " short hyaline appendage " of Montagu. 

 From their great resemblance to the tentacle-eyes of the 

 Gasteropod Mollnsca, I have little doubt that these are 

 organs of vision. If so the profusion with which the 

 Sabella is furnished in this respect may account for its 

 excessive vigilance; which is so great, that not only will 

 the intervention of any substance between it and the 

 light cause it to retire, but very frequently it will dart 

 back into its tube almost as soon as I enter the room, 

 even while I am ten feet distant. 



It is not, however, to the tube nor to the worm, that I 

 wish especially to direct the attention : yet it is neces- 

 sary that I say a preliminary word about the former. 

 Ordinarily the tubes of these worms are formed of the fine 

 impalpable earthy matters (clay, mud, etc.) held in sus- 

 pension in the sea, incorporated with a chitinous secretion 

 from the body of the animal ; and therefore the surface 

 of the tube is always rough and o})aque. But in this in- 

 dividual case, probably owing to the habitual stillness of 

 the water in the vessel not holding in suspension the par- 

 ticles of mud that ordinarily enter into the composition 

 of the tube, the latest-formed portion is composed of pure 

 transparent chitine, witliout any perce[)tible earthy ele- 

 ment. This clear terminal portion of the tube you may 

 perceive to be occupied by a curious parasite. About 

 twenty bodies, having a most ludicrously close resem- 

 blance to the human figure, and as closely imitating cer- 

 tain human motions, are seen standing erect around the 

 mouth of the tube, now that the Sabella has retired into 

 the interior, and they are incessantly bowing and tossing 

 their arms in the most ener<retic manner. 



