62 ANTIIOZOA HYDROIDA. 



Hah. — On shells and other corallines ; and on sea-weeds, common. 



Fig. 8. 



Polypidom affixed by a creeping tubular fibre, from one to four, or 

 even six, inches high, sparingly and diffusely branched in general, the 

 shoots filiform and slender, scarcely zigzag, jointed at regular inter- 

 vals, the interarticular spaces dilated upwards, the joints consisting 

 of one or two oblique twists or wrinkles. The cells are situated at 

 and under the joints ; they are alternate and rather distant, ses- 

 sile, urceolate, short, bulged at the base, the upper half free and 

 divergent, smooth, with a wide aperture looking outwards and 

 having its rim sinuated with four small denticles placed at equal 

 distances. (Fig. 8, a, b.) Polypes white or sometimes bright yellow, 

 with numerous tentacula. Vesicles large, sessile, ovate, with a short 

 tubulous apex, generally wrinkled across, sometimes smooth. After 

 the ova have escaped from it, the orifice of the vesicle is rendered 

 slightly spinous or toothed. 



Pallas describes a variety (j8. ) worthy of notice, not unfrequent on 

 the coast of Cornwall, three inches and upwards in height, with a com- 

 pound stem, and branched in a pinnate manner similar to Halecium 

 halecinum, which this variety indeed very closely resembles. Ellis 

 mentions that he had received specimens of the same from the Isle 

 of Wight : and I have found it on the coast of Berwickshire. In 

 the collection of my friend Dr. Coldstream, there are specimens also 

 from the Cape of Good Hope, of a still greater size and more robust 



