HYDROIDS OF EASTERN CAt^ADA 



175 



Thuiaria cupresslna (Linnteus). 



Trophosome. Colonies clustered; stem long, flexu- 

 ous; branching alternate but not always exactly in the 

 same plane; branches branch dichotomously and these 

 branches again do so; hydrothecfe alternate, short, the 

 free portion, about one-third, divergent, narrowed 

 towards the margin; margin bi-labiate: operculum with 

 two flaps. 



Gonosome. Gonangia obovate or triangular, with 

 two shoulder spines ; collar short. 



Thuiaria fahricii (Levinsen). 



Trophosome. Stem erect, rather rigid, branches 

 On all sides of the stem, distally forming a dense tuft; 

 repeated dichotomous branching; hydrothecfc sub- 

 opposite, narrowing slightly from base to margin, aboui 

 one- third free; margin with two teeth; operculum with 

 two flaps. 



Gonosome. Gonangia borne in two rows on the 

 branches, oblong or obovate, with circular aperture and 

 two shoulder spines. 



Thuiaria immers'a Xutting. 



Trophosome. Stem long, flexuous, branches coming 

 out on all sides in a loose spiral arrangement; main 

 branches sparingly dichotomoiisly branched; hydro- 

 thecae alternate, almost entirely immersed, tapering 

 from base to margin. 



Gonosome. Unknown. 



Thuiaria latiuscula (Stimpson). 



Trophosome. Main stem stout, rigid, mucli larger 

 than the slender, alternate branches, that are not again 

 branched; 'hydrothecae slender, tubular, tapering to the 

 margin, about one-fourth free. 



Gonosome. Unknown. 



Thuiaria lonchitis (Ellis and Solander). 



Trophosome. Main stem stout, rigid; branching 

 pinnate; branches stout, stiff, white, not again branch- 

 ed; hydrothecae alternate, tubular, but little tapered, 

 about one-fourth free. 



Gonosome. '* Gonangia borne on upper side of 

 branches, long, slender, with a round aperture, narrow 

 collar and operculum" (Nutting). 



No. 93. 



Thuiaria cupressina. 



No. 94. 

 Thuiaria fahricii. 



No. 95. 

 Thuiaria iinmersa. 



No. 96. 

 Thuiaria latiuscula. 



No. 97. 

 Thuiaria lonchitis. 



