Ivi 



INTRODUCTION. 



TABLE II. THECAPHORA. 

 Hydroida with true calycles. 



Genera. 



I Calycles erect aud free 2 



1. < Calycles adnate, disposed along the 

 ( stem and branches : 11 



f * Calycles supported on a short pro- 

 cess from the stem ; polypitesonly 



2.<( partially retractile 3 



j Without the stem-process; poly- 



t pites wholly retractile 4 



I With snake-like tentacular organs 

 3. < distributed over the ccenosarc . . OPHIODES. 



\ Without such organs HALECIUM. 



{Calycles truly campanulate or bell- 

 shaped 5 

 Calycles not campanulate 6 



t- I Calycles operculated LOVENELLA. 



I Calycles not operculated ........ CLYTIA, OBELIA, 



CAMPANULARIA, 

 THAUMANTIAS and 



GONOTHYR^Af. 



f Calycles ovato-conic J CAMPANULINA, ZY- 



GODACTYLA, 

 OPERCITLARELLA, 

 and LEPTOSCY- 

 Calycles tubular or cylindrical. ... 7 PHTJS. 



( Calycles with a conical operculum. 8 

 7. < Calycles without a conical oper- 

 ( culum 9 



{' Calycles constricted at the base and 

 pedicellate CALYCELLA. 



Calycles not constricted at the base 

 and perfectly sessile CUSPIDELLA. 



* The process immediately supporting the calycle or the jointed shoot 

 on which it rests is a projection from the stem. The calycles in this section 

 only shelter the base of the polypites. 



f In this group the trophosorne affords no generic characters. If the 

 reproductive bodies are absent, the student must treat it as a single genus, 

 and identify his zoophyte by a reference to the specific descriptions. 



I The calycles in this section are more or less ovate, becoming pointed 

 above, where the margin is cleft into convergent segments. This form must 

 be distinguished from the long, tubular shape. 



