A General History of the Marine Polyzoa. 471 



at intervals to clusters of two to five suberect branclilets, and 

 their distal extremities are arcuate, 3 to 3*5 centira. long, and 

 divided into branclilets, which, like the more central ones, are 

 2 to 3 centim. long and scarcely 5 millim. thick ; apices 6 to 

 7 millim. apart. Upper surface of the main branches and 

 base of the branclilets provided with numerous large immersed 

 corallites, with an aperture of 1 millim. Apical corallites 

 about 2 millim. diameter, usually about 1 millim. exsert. 

 Lateral corallites ascending, elongate, labellate, and imbri- 

 cate, 3 to 4 millim. long and 1*5 millim. thick, apices more or 

 less pointed. Corallum very porous and reticulate in section, 

 surface densely echinulate ; wall thin, finely striato-reticulate 

 and echinulate, except in the case of the younger ones. Star 

 not recognizable in the prominent corallites; in the immersed 

 ones it consists of six w^xy narrow septa. 



Two specimens have the apices of some of the branchlets 

 subdivided ; in a third the majority are proliferous and some 

 of the apical corallites rather over 2 millim. in diameter. 



Mauritius. 



LV. — Contributions towards a General History of the Marine 

 Polyzoa, \^^0-'d\.— Appendix. By the Rev. Thomas 

 HiNCKS, B.A., F.R.S. 



[Continued from p. 176.] 

 'Annals,' July 1881 (p. 66 sep.). 



Hiantopora ferox, MacGilli vray . 



In a previous paragraph I have pointed out that this form 

 cannot be referred to Crihrilina^ from which genus it has 

 been rightly separated by MacGillivray. Since it was 

 written I have seen Mr. Kirkpatrick's Report on the Polyzoa 

 from Torres Straits collected by Professor Haddon*, in which 

 he ranks Hiantopora frox as a variety of Membranipora 

 radicijeraj Hincks. The connexion between these two very 

 dissimilar species he supposes to be established by the dis- 

 covery of a variety of M. radicifera, to which he has given 

 the name intermedia. Granting that the latter is, as Mr. 

 Kirkpatrick supposes, a variety of M. radicifera, the further 

 development and fusion of its spinous processes may have 

 originated a form bearing a general resemblance to H. 

 ferox. Beyond this, I confess, 1 am not prepared to go. 

 Mr. Kirkpatrick goes much farther ; he assumes that 



* 'Scientific Proceedings of the Royal Dublin Society,' vol. vi. part 10. 



