104 



CCELENTERATA 



Fig. 171 



-Tubularia crocea (Agassiz). 

 B, a single hydranth. 



colony 



T. {Parypha Ag.) 

 crocea (Ag.) (Fig. 171). 

 Colonies growing in dense 

 tufts of long tangled 

 stems of from 8 to 10 cm. 

 in height ; sparingly 

 branched ; basal tentacles 

 20 to 24; apical process of 

 the female sporosac flat- 

 tened: common on piles, 

 docks, etc., in shallow 

 water from Boston south- 

 wards; California. 



Order 4. CAMPANULARIAE.* ( Calyptoblastea ; Leptomedusae. ) 



Colonial hydromedusans with two kinds of polyps (Fig. 172), the 

 hydranths or the nutritutive polyps and the blastostyles or the reproduc- 

 tive polyps. The perisarc does not end at the base of the polyp, as in 

 the tubularians, but continues over it, forming, in the case of the 



hydranth a protective cup called the hydro- 

 theca and in the case of the blastostyle a 

 cylindi'ical capsule called a gonangium or a 

 gonotheca. In some species the open end of 

 the hydrotheca may be closed by projections 

 or valves which form an operculum (Fig. 

 173); in some species also the blastostyle 

 projects out of the mouth of the gonangium 

 and forms a large cap- 

 sule or brood jchamber 

 in which the eggs de- 

 velop, called the acro- 

 cyst (Fig. 178). The 

 hydranth has never 

 more than a single 

 whorl of tentacles and 

 can in most cases be 

 retracted within its 

 hydrotheca or extended 

 blastostyle cannot usually be extended beyond its 



Fig. 172- — A campanularian 

 liydroid (from Ilogner). 1, 

 hydranth ; 2, hydrotheca ; 3, 

 blastostyle ; 4, gonangium. 



bevond it. The 



Campanularian oper- 

 cula (Nutting). A, 



two-valved operculum; 



B, one-valved opercu- 

 lum. 



gonangium and produces within it the gonophores; these constitute 



* See "The Leptor;cdusae of the San Diego Region," by II. B. Torrey, Uni. of 

 Cal. Pub., Vol. 0, p. 11. 



