Mr. A. H. HassalPs Catalogue of Irish Zoophytes. 167 



believing in their animal nature from their structure and che- 

 mical composition. 



I have here to acknowledge the obligation I am under to 

 Dr. Johnston* of Berwick, who kindly afforded me the benefit 

 of his experience wherever I entertained doubts as to the iden- 

 tity of any of the species mentioned, and from whose assist- 

 ance, in this particular, I am enabled to present this Catalogue 

 with the greater confidence. 



RADIATED ZOOPHYTES. 

 Order I. ZOOPHYTA HYDROIDA. 



TuBULARIADiE. 

 TUBULARIA. 



Tubularia indivisa. — Dublin bay ; not common. 



T. ramea. This is one of the most delicate and arborescent of the 

 corallines, exactly resembling a miniature tree. The ultimate tubes 

 have four or five distinct rings at their base. Polypidom about six 

 inches in height. 



On shells from deep water ; rare. Blackrock, Dublin bay. 



SflRTULARIADiE. 



Thoa. 



Thoa halicina. A variety of T. halicina is frequently met with, 

 distinguished from the ordinary specimen by its irregular mode of 

 branching. 



Dublin bay ; common. 



T. Beanii. Of this extremely elegant zoophyte I have met with 

 several specimens, averaging from four to six inches in height. There 

 is a great resemblance between Thoa Beanii and the preceding, with 

 the variety of which it may be readily confounded, particularly when 

 deprived of its very characteristic vesicles. It may, however, be 

 known from it by the branches passing from the main stems nearly 

 at right angles, but at unequal intervals, and by its being irregu- 

 larly ringed, having also a joint between each cell, in which re- 

 spect it agrees with T. halicina. 



Sertularia. 

 Sertularia polyzonias. Between this and the one following there 

 is a manifest relation. They are both usually found upon Flustra 

 foliacea, though not confined to it. 

 Killiney bay; not common. 

 <S. rugosa. — Kingstown ; not common. 



S. rosacea. Usually found as a parasite on S. cupressina and S. 

 Tamarisca, particularly on the former. 

 Dublin bay ; abundant. 



* I have followed the Arrangement and Nomenclature given in Dr. J.'s 

 admirable work on British Zoophytes. 



