THE DRAWING OF THE SEINE. 185 



thirty-second of an inch in diameter. By this descrip- 

 tion alone you might not recognize them, but, besides 

 the features enumerated, these statoblasts have a series 

 of hooks ranged about their outer rim which establishes 

 their identity. Think of fifteen pairs of fish - hooks, 

 placed back to back, and ranged at uniform distances 

 from each other, in clusters of two, around a small coin, 

 and yon will have a fairly good idea of a Pectinatella's 

 statoblast. These statoblasts are enveloped in gelatine 

 until after death of the colony, it being needed in order 

 to protect the parent from laceration by the pointed 

 booklets, and so is retained until lost by exposure of 

 the bud to external influences. After the statoblasts 

 are free from their parents, they still " lie loose in the 

 ccenoecial cavity from this time until the death and de- 

 cay of the polypides destroy the upper parts of the 

 cells. Through the openings thus made, being lighter 

 than water, they are readily floated off, and pass the 

 winter unprotected by any other covering than their 

 cellular casings, although remaining near the surface, 

 and consequently, in higher latitudes, imbedded in the 

 ice for several months. " Growth begins at the ap- 

 proach of spring, and the edges of the sheath are split 

 apart by the increasing bulk of the polyzoon, which 

 protrudes between them. 



" The organs, when the little animal first makes itself 

 visible, are well advanced in growth, and the polypide is 

 already capable of retraction and expansion. For a 

 time it floats freely in the water, wafted about by the 

 cilia, which clothe the whole external surface, and in- 

 creases in size until the sheaths of the statoblasts can 



