400 APPENDIX. 



more than ^ to ^^ inch long, and very closely set, so that 

 the whole poh^idom has the most exact resemblance to a 

 beautiful silky quill feather. 



10. P. Macgillivrayi, n. sp. 



Cells campanulate, deep, rounded at bottom; margin 

 subphcate, entire. Rostrum large, rising from the cell, 

 adnate the whole length of, and as long as, the cell ; the 

 upper thu'd constitutes a cup distinct from the lower por- 

 tion ; lateral processes adnate, wide, short, curved upwards, 

 canalicular or tubular. Costss of ovarian receptacle con- 

 nected by a membranous expansion. 



Hab. — Louisiade Archipelago, reefs at low water. 



Colour bright brownish buff. Polypidom six to seven 

 inches high, consisting of a strong central stem, giving off 

 opposite branches, at regular intervals, and bifariously 

 disposed. Pinnules about J inch long, closely set. 



h. GjTnnocarpese — o^dcels naked. 



11. P. effusa, n. sp. 



Cells urceolate ; deeply emarginate posteriorly, entu'e in 

 front, ventricose below ; a small pedunculate infandibuli- 

 form process attached in front to the projecting portion 

 of the rachis on a level with upper border of the cell. 

 Ovicell— ? 



Hab. — Prince of Wales^ Channel, Torres Strait. 



Colour buff. Habit very peculiar. The poh^^idom rises 

 to a height of seven or eight inches, with a long slender 

 waving, but upright stem, which is naked inferiorly, and 

 above gives off numerous straight or waving branches, 

 again sub -dividing into other shorter straight ramules, 

 about an inch long. The branches and branchlets are 

 both pinnulated ; the pinnules are not more than ^ to ^ 

 inches long, extremely delicate and minute, so as in the 

 dry state to be scarcely visible. The transition from the 

 former section of the genus Plumularia to the present, is 



