FROM THE LOYALTY ISLES, NEW GUINEA AND NEW BRITAIN. 443 



Measurements : zooecia from '69 mm. to '89 mm. in length x '26 mm. in width. 

 ooecia "24 mm. x "24 mm. 



The position and structure of the ovicell are the characteristic features which 

 differentiate this species from Didymia drnplex, Busk, (Brit. Mus. Cat. I. p. 35). The 

 ooecial cell does not occur at the bifui-cation of a branch as in Busk's species, but 

 in the middle line of an internode interposed between two ordinary zooecia, so that 

 here the branch has three cells at the same level. There are several ovicells in an 

 internode placed one above the other, and occasionally the fertile cells seem to be 

 succeeded by an additional line of sterile zooecia so that the branch becomes triserial. 

 This apparently occurs at the end of a branch only. The ooecial cell has the same 

 structure as the other cells and does not present the peculiarities found in Didymia 

 simplex. 



S. Bugula dentata, Lamourou.x. Busk, Brit. Mus. Cat., I. 46. 



The zooarium is delicate and of a leaden blue colour. There are two spines at 

 the upper inner angle, the lower one being the shorter ; one spine at the upper 

 outer angle, and two placed together further down on the outer side. All the spines 

 point upwards except the last on the outer side which is directed inwards. 



9. Bugula avicularia, Linnaeus. 



There is only one small fragment of this species. 



10. Bugula yieritina, Linnaeus. 



Growing on a Nautilus shell. A\dcularia occur at the base of a few cells. 



11. Tubucellaria cereoides, Ellis and Solander. 

 Very common. 



12. Cribrilina radiata, var. /3, Hincks. Hincks, Brit. Mar. Pol, p. 185. 



The zoarium forms a silvery white crust over Terebratella shells. The zooecia are 

 oval and very minute (from '20 to -29 mm. in length x '14 to '20 mm. in width). 

 The ridges are not prominent; the interstitial pores are large. The central keel is 

 inconspicuous ; the small umbo below the mouth is most clearly seen in the fertile 

 cells. The ordinary zooecia bear six spines round the mouth, the fertile cells two on 

 each side. The ovicell has an indistinct keel. The avicularia occun'ing between the 

 cells are elongate ; vibraculoid appendages are wanting. 



13. Memhranipora rudicifera, Hincks, var. intermedia, Kirkpatrick. Kirkpatrick, 

 Sci. Proc. Roy. Dub. Soc, Vol. VI. p. 615. 



The form of the spines characteristic of Kirkpatrick's variety is clearly seen in 

 the young zooecia near the margin. On one side of the orifice is the .spine bearing 

 the avicularium, and the horizontal bifurcating branch sjoreading over the whole area. 

 This limb bifurcates repeatedly, the ultimate branches being slender. On the opposite 

 side there is a bifurcated spine of which the vertical branch is again bifurcated at 



