Hydroida from Iceland. 149 



20-30 fathoms. " On the stems of Eudendrium cajnllare^ 

 Alder, which is often ahnost covered with its little transparent 

 caljcles and reproductive capsules, as with a fine down" 

 (G. O. Sars). 



Calycella pygmcea^ Alder, PI. VII. fig. 15. 

 On other Hydroids. 



Calycella obliqua^ n. sp. PI. VI. figs. 4, 5. 



Stem erect, simple, rooted bj a filiform stolon. Hydrothecm 

 alternate, elongate, tubular (height more than four times as 

 great as the breadth) , gracefully curved, the convex side upper- 

 most, obliquely truncate above, furnished with an internal 

 membranous operculum, and borne on short ringed pedicels. 

 Gonothecce unknown. 



This very distinct and elegant form is at once distinguish- 

 able from all its kindred by its obliquely tnincate hydrothecee. 

 The wall of the calycle on one side for a short distance below 

 the margin seems to be simply membranous, and to fold 

 inwards slantwise across the tube, so as to form a kind of 

 internal operculum. 



Several specimens have occurred growing on other zoo- 

 phytes. 



Calycella quadridentata^ n. sp. PI. VIII. figs. 17-20. 



Ilydrotliecce cylindrical, usually slightly incurved on one 

 side, the height about three times as great as the breadth, with 

 a quadridentate margin and an operculum composed of four 

 pieces, borne on ringed pedicels of variable length (3-7 rings), 

 which rise at intervals from a creeping stem. GonotJiecce un- 

 known. 



This species, which bears a general resemblance to C. sy- 

 ringaj is at once known by the quadridentate rim of the 

 ealycles and the quadripartite operculum. The denticles on 

 the margin are well marked ; and the operculum is composed 

 of four broad and short segments, corresponding with the 

 spaces between them ; whereas in C. syringa it is made up of 

 as many as eight or nine rather narrow and elongate pieces, 

 forming a somewhat elevated cone (PI. VIII. fig. 24). The 

 ealycles are of the same general shape in the two species ; but 

 the outline is stiffer and less wavy in C. syringa than in the 

 present form. The pedicel of C. quadridentata is rather thicker 

 than that of its ally, and is usually, as far as I have observed, 

 short (3 or 4 rings), though sometimes the number rises as 

 high as seven. 



