UYDROIDS OF I:ASTKRY CANADA 



169 



No. 74. 

 r.afira fruticosa. 



No. 75. 

 L<tf(ia (jracilliina. 



Lafcea fruticosa Sars. 



Trophosome. Stem fascicled, with many large 

 branches regularly arranged; pedicels long with three 

 or four twists, passing out at an angle of 45° to 60° 

 from the stem; hydrothecte slightly convex with the 

 lower wall more nearly in line with the pedicel than 

 the upper. 



Gonosome. Coppinia with lonji' hydrothecir curved 

 spi rally. 



Lafa'a f/raciUima (Alder). 



Trophosom'\ Stem fascicled, very much hranclied 

 but the main stem is indistinguishable from the 

 branches; hydrothecae long, tubular, convex, coming off 

 from the stem at an angle of less than 45° ; pedicels 

 with one or two twists. 



Gonosome. Coppinia similar to that of L. diimosa 

 but the gonahgia as viewed from the surface are more 

 nearly circular than hexagonal. 



Lafcea. pygiiya Hincks. 



Ti-ophosoiiie. Stem creei)iiig; hydrothccic small, almost sym- 

 metr'cal ; pedicels with two or three twists. 



Gonosome. Coppinia oval, tubes long, stout, strongly bent, forming 

 a com]ilete network around the gonangia. (According to Broch.) 



Trophosome. Stem erect, fascicled, irregularly branched 

 hydrotheca? symmetrical, coming oif from the stem nearly al 

 right angles; pedicels longer th3n in other species, with fivf 

 or .six annulations or twists. 



Gonosome. " Coppinia with regular hexagonal facets in 

 the middle of which is a tubular opening; the tubes are com 

 paratively few in number, very thick and strong, quitf No. 77. 



irregularly curved" (Bonnevie). ^^"Z"'- -^J/"' """•««• 



Family SERTULARID/E. 



Trophosome. Hydrotheeae sessile, usually arranged on l)otli sides of the stem 

 or branches and more or less adnate to them. 



Gonosome. Gonophores producing fixed sporosacs. 



KEY TO GENERA. 



a Hydrotheca? all on one side of the branches, their distal ends alternating right 

 and left. Hydrallmania. 



aa Hydrothecae arranged in two longitudinal rows. 



h Hydrothecffi in opposite pairs. Sertularia. 



hh Hydrothecse alternate. 



c Operculum of one adcauline flap. 



d Hydrothecal aperture small, body flask-shaped. Ahl'iinarw. 



dd Hydrothecal aperture large, body not flask-shaped. Diphasia. 

 cc Operculum abcauline or with more than one flap. 



e Operculum of three or four pieces. Sertularella. 



ee Operculum of one or two pieces. Thuiaria. 



aaa Hvdrothecse arranged on all sides of the branches. Selaginopsis. 



