ANALYTICAL INDEX. 



263 



CHAPTER lV.—co)itinued. 



§ 4. SeETDLABIA rosacea, ..... PAGE l.Dtl 



Hydra with 22 tentacula, . . . . • 160 



Vesicles large and peculiar, . . . • . ib. 



Metamorphosis of the planula from them, ... ib. 



•Plate XXVI., figs. 1-13, ib. 



§ 5. Sertularia pumila, . . . • • .161 



Articulation is a pair of cells, .... ib. 



Hydra with 19 or more tentacula, . . . .162 



Globular and ovoidal vesicles, .... ib. 



Plate XXVI., figs. 14-21, ib. 



§ 6. Sertularia ualecina and Cognates, . . . 162 



1. This species is indistinctly characterized, . . .163 



Plate XXVII., il'- 



Hydra with 18-22 tentacula, . . . • . ib. 



Regenerating hydras develope from the summit of the pith, . 165 

 Number regenerating from a twig, .... ib. 



Propagation, . . . • • ■ 166 



Vesicles, green and yellow, of various configuration, . . ib. 



Green and white planulaj from the same specimen, . . ib. 



Metamorphosis of the planula, . . . . .167 



Spine from the smaller extremity, .... ib. 



Anomalies — peculiarities, . . . . . ib. 



DiflTerent vesicles on the same specimen, . . . 168 



Three hundred nascent Sertularia) in February, . . .169 



Hydra; issuing through vesicles, .... ib. 



2. Sertularia (T/ioaJ Beanii, . . . ■ . ib. 

 Hydra with 20-24 tentacula, . . . ' . ib. 

 Vesicle peculiar, . . . • . .170 

 Planula metamorphosis to Sertularia in si.x days, . . ib. 



3. Cognvitea ol Sertularia halecbin, . . . .171 



Stem consisting of tubuli, . . ... . ib. 



Vigorous regenerations, . . . . . ib. 



Specimen with 400 yellow vesicles, .... ib. 



Colour of the vesicle from its contents, . . . .172 



Planuloe discharged during weeks, .... ib. 



Origin of vesicles obscure, . . . . .173 



External impressions on hydraj, .... ib. 



Sertularia halecina favourable for observation, . . . ib. 

 Plates XXVII., XXVIII., XXIX., XXX., XXXI., explained, 174 



§ 7. Sertul-^ria muricata, . . . . .175 



Hydrai with 22-24 tentacula, .... ib. 



