Poly zoa from Port Phillip. 17 



haps form a dendritic growth, D'Orbigny describes the 

 branches of lieteropoj'a cervtcornis as being provided with 

 large transverse tubercles, forming crests, with the cellules 

 arranged along the middle, the base and intervals of these 

 groups being pierced by a number of intermediate pores. In 

 H. mceandrina the pores are deficient along the crests and fill 

 up the floor of the depressions. 



Along the length of the zooecial tubes the pores and so- 

 called septa can be seen as in other species of Heteropora. 



Suborder Ctenostomata. 



Family Alcyonidiidae. 



Genus Alcyonidium, Lamouroux. 



Alcyonidium mytili, Dalyell. (PI. II. figs. 6, 6a.) 



The cells are hexagonal and the septa between the cells 

 distinctly visible. 



Hah. Incrusting the stems and branches of Amathice. 



The incrusting growth is probably not parasitic on the 

 Amaihia^ since the contents of the biserial groups of cells of 

 the latter are not absorbed, but \}aQAmatMa forms an efficient 

 axial support. In Great Britain A. my till incrusts shells, 

 stones, and Algje. 



Oeographical distribution. Great Britain, Cattegat, Baltic. 



Family Vesiculariidse. 

 Genus Amathia. 



The following species of Amathia were represented in 

 this collection : — 



Amathia australis, Tenison- Woods. 



hicornis^ Tenison- Woods. 



hiseriata^ Krauss. 



connexa^ Busk. 



. lendigera^ Linn. 



Wilsoni, n. sp. 



pinnata, n. sp. 



Brongniartii^ Desraarest & Lesueur. 



Amathia hiseriata^ Krauss. 



Amathia biseriaia, Krauss, Corallineen und Zonphyten der Siidsee, 

 p. 23, fig. 1, «, J, c. _ 



? Anutthia inm-7nata,'M.?i.Q,G:i\\i\riij, Trans. R07. Soc. Vict. vol. xxiu. 

 p. 183. 



Ann. & Mag. N. Hist. Ser. 6. Vol. ii. 2 



