6n 



As we liave liad ocrasion to menfion tlie crropt resonrcos 

 of nature in efi'eotine: her ohjects, so we may now notii-e 

 the wonderful economy she observes in ni,)kinsj tliose 

 resources subservient to dKTerent purposes. Tiie water not 

 only serves as a fulcrum for muscular action, but {"or the 

 purposes of respiration and the perfection of the ova ; and to 

 each of these functions it is equally indispensable. The 

 function of primary inportance in all animals appears to be 

 the respiratory ; if this be deranj^ed in these creatures we 

 soon see the stran<re condition into which they are thrown, 

 and the contrast it forms with the healthy state, in which 

 every function beau!ifully depends on the others. If an Ac- 

 tinia be placed in deteriorated water, it endeavours to make 

 lip in the quantity what it loses in the quality of the water. 

 It imbibes so much as to distend the body to an enormous 

 extent; so much as to make it resemble an inflated bladder, 

 rather than the animal it is. I'he pressure of the water 

 behind forces the stomach out of the mouth, which together 

 with the white threads, hanii;s in transparent lobes over the 

 sides of the animal. As the respiration appears to be carried 

 on chiefly by vibratory cilia, and these filaments and the 

 stomach are clothed with them, their exposure e;reatly assists 

 the process by enlarging the surface and exposing it to more 

 water. The ova also suffer a considerable check in their 

 deve'opement, hence many that have been kept in unfavour- 

 able positions on the shores have never increased, and having 

 become transparent, it could be seen that the ova were very 

 imperfectly develoiied in any and in some not at all ; and 

 there they are and have Been for two years and half, the 

 same in number, though difiVrent in appearance. Those 

 always thrive best that are most exposed to the violence of 

 the sea. When thus distended their muscular energy is 

 always diminished and sometimes nearly destroyed ; a fresh 

 supply of water, however, soon redeems them to their 

 healthy state. 



The manner in which the developcment and exclusion of 

 the ova takes place is still an undecided question. No one, 

 however who has watched these creatures, can have failed 

 to observe the fully formed animals expelled alive through 

 the stomach ; nor can any one who has been in the habit of 

 dissectins; them have failed to notice the young animals in the 

 interseplal spaces, exterior both to the ovaries and the 

 threads, supposed by some to be oviducts. JMr. Tcale's ex- 

 planalion seems to bo the best, as it fully accounts for all the 

 positions in which the younir have been found. He thinks 

 that when the ova arc suHiciently matured, they burst their 

 membranous envelope and " become lodged in the inter- 

 septal spaces;'' from these points they can travel into the 



