SERTULARIA. 197 



latent germs, subsisting previous to origination of the horizontal thread, 

 B, /;. 



From these and other observations, we may reach the following con- 

 clusions : — 



I. Reproduction from different halves of a bisected stalk may ensue, 

 at the point of bisection, in opposite directions, being upwards from the 

 under half, and downwards from the upper half. 



II. Hydrae with their cells are generated on both reproductions, if 

 vigorous ; if feeble there will be none. 



III. A hydra has originated and attained maturity in twelve days 

 from such reproductions ; and one has survived forty days. 



IV. An originating portion, having 3 incipient cells on October 31, 

 had acquired 33 mature cells on December 15, or in 45 days. 



V. All the new parts are at first pure white, which, in time, is con- 

 verted to yellowish-brown. 



VI. The arrangement of new parts is by simple divergence in the 

 same plane : an arrangement altogether different distinguishes the adult 

 Sertularia. 



VII. Original cells are obliterated by new branches germinating in 

 the line of their axis. 



VIII. Vesicles of various configuration are borne by adults, contain- 

 ing from one to four yellow spherules, developing as planulse. 



IX. The planulse discharged by the vesicles have become motionless 

 in three days ; and the hydrse of nascent Sertularise, generated by their 

 metamorphosis, have attained maturity in ten days after the planulse issued 

 from the vesicles. 



Plate XXXVII. Sertularia argentea. 



Plate XXXVIII. Sertularia argentea. 

 Fig. 1. Branch. 



2. Section of the branch of an adult specimen, comprehending a com- 

 plete articulation, a h. 



