ANALYTICAL INDEX. 



:irw 



( II A PTER VI. — continued. 



Single hydra from an ovum, .... page I < i? 



Survivance of the Alcyonella, . . . . 108 



Alcyonio mass, ...... ib. 



Plate XXIX. explained, .... 109 



(2.) Alcyonella gelatinosa, .... ib. 



Resembles frog's spawn, . . • • • 110 



Hydra with 70 tentacula, ..... ib. 



Ceases to protrude in October, . • • 1 1 I 



Ova escape on its decay, . • • • • >b. 



Specimens reappear after disappearing for years, . . 11'-' 

 Substances invested, . . . . • .113 



Wherein different from Alcyonella stagnorutn ? . 114 



Nature of the hydra, . . ■ • . ib. 



Trembley's Polypes a pannache, . . ■ 115 



Food from muddy solutions, ..... ib. 



Propagation, ■ ■ ■ ■ • • l' 1 ' 



Involuntary motion of the ova, . . . . ib. 



Their circumference smooth, .... ib. 



Caution in experiments, . . . . .117 



Method of obtaining the young, . . . . 118 



Brood from ova, . . • • ■ .119 



Young with 32 tentacula, .... ib. 



Second, third, fourth generations from a first brood, . . 120 



Vesicles of uuknown nature, .... ib. 



Bottom of a boat invested by Alcyonella?, . . . 121 



Hydra secured by eight ligaments, . . . 122 



Plate XXX. explained, ..... ib. 



§ 3. Plumatella, . ■ • • • • l- :; 



Are there more species than one ? . • . ib. 



Plumatella repens spreads from a centre, . . 124 



Specimen from Fenton Tower described, . . . I2.J 



Hydra with 70-80 tentacula, .... ib. 

 Inorganic parts tubular, . . • • .120' 



Specimens adhere laterally, . . ■ • 127 

 Pulsation in the hydra ? . . ■ . .12s 



Hydra infested by the Vortieelta rotatoria, . . 12!) 



Specimens investing metal, ..... ib. 



Perpetuation, ..... ib. 

 Whole skeleton tubular, . . . . .130 



Ova occupy the skeleton and the hydra, . . . ib. 



Contents matured in 198 days, .... ib. 



