SEA-MATS AJSD SHELLY COEALLINES. 69 



shell at the bottom of the sea, yon would have seen 

 much more. And what would then have appeared, I 

 will describe to you. 



Suppose, then, that a coverlid of transparent skin 

 were stretched over each cradle, from a little within 

 the margin all round, leaving a transverse opening just 

 in the right place, viz. over the pillow, and you would 

 have exactly what exists here. There is a crescent- 

 form slit in the membrane of the upper part of the cell, 

 from which the semicircular edge, or lip, can recede, 

 if pushed from within. 



Suppose, yet again, that in every cradle there lies a 

 baby, with its little knees bent up to its chin, in that 

 zig-zag fashion that children, little and big, often like 

 to lie in. But stay, here is a child moving ! Softly ! 

 He slowly pushes open the semicircular slit in the cov- 

 erlid, and we see him gradually protruding his head 

 and shoulders in an erect position, straightening his 

 knees at the same time. He is raised half out of bed, 

 when lo ! his head falls open, and becomes a bell of 

 tentacles ! The baby is the tenant-polype ! 



" This is a very amusing romance," you say. Nay, 

 it is no romance at all. If you will excuse the homeli- 

 ness of the comparisons, I will venture to affirm that a 

 personal examination of the creature itself would justify 

 their correctness, and you would acknowledge that they 

 could scarcely be more apt. 



Moreover, the globular chambers show signs of life ; 

 their front doors suddenly open, gape widely, and then 

 shut with a snap ; and presently this opening and shut- 

 ting is repeated. The meaning of this action you will 

 better understand when we see analogous organs in an- 

 other form of the same class of animals. Meanwhile, I 



