296 THE AQUARIAN NATURALIST. 



same order as that of the rings, namely from behind 

 forwards. 



It would be tedious to follow hour by hour the 

 growth of these young Terebellse ; suffice it to glance 

 at the condition in which they are found when just 

 about to leave the gelatinous mass in which they 

 have been nursed during the first period of their 

 existence, that is, at the end of the third or fourth 

 day from the birth, at which time they are strong 

 enough to issue forth and begin the world for them- 

 selves. 



At this period they present the appearance of 

 minute worms, not more than one-twelfth of an inch 

 in length. The head is distinctly formed, and pro- 

 vided with a pair of eyes. The part of the body im- 

 mediately behind the head, which at first was without 

 any trace of division, and covered with vibratile cilia, 

 seems now to represent three rings, of which only the 

 anterior is ciliated, and the two posterior devoid of 

 any appendages. The four or five segments which 

 come next are each furnished with a pair of fleshy 

 tubercles supporting setae, and to these succeed two 

 or three rings as yet devoid of appendages; while 

 the tail or last segment, still densely ciliated, has 

 undergone little or no change. 



As growth goes on, the number of segments in- 

 creases, and they are all provided with locomotive 

 oars in the shape of setiferous appendages. The Tere- 

 bella in this condition exactly resembles one of the 

 erratic Annelid ans, and has not the slightest resem- 

 blance to a tube-inhabiting worm, such as it will after- 

 wards become ; in short, it is provided with a distinct 



