Dr. Reid on the Development of the Medusse. 29 



all parts of the external surface, but most frequently near the 

 lower part, of the body. On many of the larger larvse several 

 buds were seen growing at the same time (fig. Wa). As a bud 

 enlarges it becomes elongated and attenuated at its free extre- 

 mity, and bends itself downwards to reach the surface of the 

 stone to which the elongated extremity adheres : after this the 

 attached end is gradually separated from the body of the parent. 

 When thus detached, a small opening presents itself at its upper 

 end, its interior gradually becomes hollowed out and cilia grow 

 upon it, and tentacula commence to sprout around the mouth, 

 exactly in the same manner as in the buds formed on the upper 

 surface of the stolons. The outer surface of the buds is also 

 covered with very fine cilia. Several of the buds were found 

 lying loose at the bottom of the vessels in which the stones are 

 kept, probably detached by accident, and these after a time fixed 

 themselves to the surface of the vessels, and passed through 

 their development into larvjB in the same manner as those that 

 adhered for a longer time to the bodies of their parents. One 

 of these detached buds fixed itself at two separate points, and 

 two mouths, each furnished with its own tentacula, were formed 

 at opposite ends of its upper surface. When a bud was deve- 

 loped on a stolon, the connecting part between the bud and the 

 parent was more frequently absorbed, or at least disappeared, at 

 other times the bond of connection remained ; so that occasion- 

 ally two, three or more larvse of difierent or of nearly equal size 

 might be seen growing closely united together at the base, as if 

 one had split itself longitudinally into two or more separate in- 

 dividuals. This chiefly took place when the larvse were so thickly 

 clustered together that they had not room to spread sufficiently. 

 When the buds were developed into young larvse, these generally 

 moved outwards from their parents to a small distance, leaving 

 room for those that were to succeed them. This locomotion is 

 generally slow, — one larva that I watched moved ^^^ths of an 

 inch in fourteen days, — and is effected by a sliding motion of 

 the attached end over the substance to which it adheres. In this 

 motion the attached end bulges outwards in the direction it is 

 about to take (fig. 12 a), and the whole of this end gradually 

 follows, carrying of course the whole of the upper part of the 

 body along with it. More rarely they move more rapidly by 

 pushing outwards a narrow prolongation similar to a long sto- 

 lon (fig. 4 a), which becomes fixed at its further extremity, and 

 the attached end becoming loosened, the whole body is carried 

 onwards by the contraction of the prolonged part. The older 

 larvse are almost or entirely stationary. 



The larvse, when detached from the surface to which they are 

 adherent, can again fix themselves. I have frequently performed 



I 



