236 SERTULARIID^. 



SEUTULAKELLA POLYZONIAS, Gray, B. M. Kadiata, 68. 

 COTULINA POLYZONIAS, Ayassiz, N. II. U. S. iv. 350. 



Plate XLVI. fig. 1. 



STEMS slender, slightly ivaved, irregularly branched ; 

 BRANCHES subflextious, alternate, but produced at unequal 

 distances, often themselves much and variously branched, 

 jointed obliquely ; HYDROTHEC/E placed immediately be- 

 low the joints, distant, urceolate, bulging below, above free 

 and divergent, with a wide, everted and ^-toothed aper- 

 ture ; GONOTHEC^E produced at the base of the calycles, 

 large, ovate, wrinkled transversely, with a tubular quadri- 

 dentate orifice, and shortly stalked. 



S. POLYZONIAS presents many varieties of size and habit ; 

 but the shape and arrangement of the calycles suffice for 

 its identification amidst them all. It is often of very 

 luxuriant growth, forming large, arborescent masses, which 

 exhibit the most complex ramification. The main portion 

 in such cases sends off at intervals long, slender shoots, 

 which in their turn originate a whole system of offshoots, 

 each of them much branched, the whole constituting a 

 perfect tangle of interlacing stems. Such masses, when 

 freshly cast upon the shore, and before the evanescent 

 colour has faded, have a certain exquisitely delicate beauty, 

 and may almost be said to glitter on the dark heaps of 

 seaweed. Between tide-marks the species is of much 

 humbler growth. 



When living, S. polyzonias is of a bright straw-colour 

 and is certainly one of the prettiest, as it is one of the most 

 generally distributed, of the Hydroids. It is a littoral as 

 well as a deep-water species, having a wide range bathy- 

 metrically no less than in space. It is in truth a cosmo- 

 politan form, having been met with in most parts of the 

 world. 



The polypites are large, and have 20 or more ten- 

 tacula. The female reproductive capsule contains a 



