150 



COELENTERATA. 



more nectocalyces opposite in pairs. Cormidia without bracts. Gonophores 

 reach maturity while attached to the stem ; no free eudoxids or ersaeids. 

 Hiylpopodius Q. and G.; Polijphyes H. ; Vogtia Kolliker. 



Section 2. PHYSONECTAE. PHYSOPHORA. 



-Pa 



1 



Siplionanthae /rifh a pneumatocyst and several nectocalyces (or 



bracts instead), and pal- 

 pom. Cormidia oi-ilinatt' 

 or irregular. 



The Physonectae include 

 monogastric and polygastric 

 forms. 



The stem carrying the 

 cormidia is either short, 

 sometimes spread out in 

 the form of a sac (Fig. 

 125), or elongated and 

 spirally twisted (Fig. 126). 



The small, often brightly 

 coloured apical pneurnato- 

 phore is without a terminal 

 opening of the pneumato- 

 cyst, though sometimes an 

 opening near its base may 

 be made out. The endo- 

 dermal space of the pneu- 

 matophore itself is usually 

 divided by a number of 

 radial septa into pouches, 

 while the invaginated pneu- 

 ruatocyst is divided into 

 two communicating parts 



h /^ J k \ an iipper part with a 



J \\^ 4 J ( chitinous lining, and a 



lower part with a thick 

 glandular lining. The latter 

 is called the air funnel. It 

 is the gas gland and its 

 lining secretes the gas of 

 the pneumatocyst. The nec- 

 tocalyces (except when replaced by paddling bracts with rudimentary 



FIG. 125. Physophom Jiydrostatita. Pn pneumato- 

 phore ; S nectocalyces arranged in a double row 

 on the stem ; T palpon ; P siphon with tentacles 

 Sf; Nl; groups of nematocysts (cnidosacs) ; G 

 clusters of gonophores. 



