72 



ANTIIOZOA IIYDROIDA. 



Fig. 12. 



under the angle of divergence, the aperture plain, sinuated on the 

 proximal margin (Fig. 12, a.) : Vesicles produced from the upper 

 side of the pinnae, oval, truncate above, and quadrangular, with a 

 spine produced above from each angle, the opening central and 

 papillous. (Fig. 12, b.) 



There is a slender variety with the free portion of the cells more 

 elongated than usual, so that they resemble considerably those of 

 S. rosacea, from which it cannot be easily distinguished except by an 

 examination of the ovarian vesicles. (Fig. 12, c, d.) 



10. S. Margareta, pinnate ; cells nearly opposite, tubular, 

 tlie upper half elongate ., free and divergent, with a wide plaiti 

 aperture ; " vesicles four-sided, armed with eight long teeth.'''' 

 R. A. Tudor. 



Sertularia Margareta, Hasscdl in Ann. and Mag. Nat. Hist. vii. 284, pi. vi. fig. 3, 4. 



Hah. — Mouth of the Mersey, Cheshire, Mr. Tudor. " Dredged 

 up off Howth, sparingly ; also found near the Giant's Causeway," 

 A. H. Hassall. Collected by William H. Harvey, Esq., in Dublin 

 Bay, in 1 834, W. TJioni2')Son.* Devonshire, Mrs. Griffiths. 



Polypidom adhering by tortuous tubular fibres, and rising, usually 

 in a graceful bend, to a height of three or four inches, of a pale horn 

 colour, darker near the base and in the stalk, pinnate, the rachis 

 straight, celliferous, the pinniB rather close, regularly alternate, patent, 

 simple : Cells opposite or nearly so, three in the intervals between 

 the origins of the pinnae, two or three pairs between their joints, 

 tubular, the upper half free and divergent, curved on the upper 

 side, with a wide unconstricted aperture, the texture thin and smooth. 



* Mr. Thompson sent me specimens in March 1839, bnt the doubts I had ex- 

 pressed of the species prevented its being then named as distinct. 



