ZOOPHYTA HYDKOIDA. 91 



(June 1st) the cells were evidently filling again, although no 

 tentacula were visibly protruded, but on the afternoon of Friday 

 (June 2d) every cell had its polype complete, and displayed in 

 the greatest perfection. Had these singular facts been known 

 to Linnteus, how eagerly and effectively would he have impres- 

 sed them into the support of his favourite theory ! Like the 

 flowers of the field the heads or " flores" of these polypidoms 

 expand their petaloid arms, which after a time fall like blighted 

 blossoms off a tree ; — they do become " old in their youth," 

 and rendered hebetous and unfit for duty or ornament by age or 

 accident, the common trunk throws them off, and supplies its 

 wants by ever-young and vigorous growths. The phenomena 

 are of those which justly challenge admiration and excuse a so- 

 ber scepticism, so alien are they to all we are accustomed to ob- 

 serve in more familiar organisms ; but besides that faithful ob- 

 servation renders the facts undeniable, a reflection on the history 

 of the Hydra might almost have led us to anticipate such events 

 in the life of these zoophytes. " Verily for mine owne part, 

 the more I looke into Nature's workes, the sooner am I induced 

 to beleeve of her even those things that seem incredible." 



I arrange the British species of this order under the follow- 

 ing families and genera : 



Family I. HYDRAID.F:. 

 Polypes gemmiparous, the young pullulating from the body of the 



parent. 



1. Hydra. Polypes naked, single, locomotive. 



Family II. TUBULARIAD/E. 

 Polypes gemmiparous, the gemmules naked, pullulating from the 



bases of the tentacula. 

 * No Poly2)idom. 



2. CoRYNE. Polypes naked, the tentacula filiform. 



3. Hermia. Polypes tunicated, the tentacula with glandular tips. 



** A distinct polypidom. 



4. TuBULARiA. Polypes not retractile within cells : Polypidoms 

 listular, simple or branched. 



