Ill 



magellanica^, and of which species this writer has been so kind to send me a 

 fragment, there is an operculum: 



Hiantopora Mac Gill.^, char, emend. 

 The strongly calcified zocecia are connected by cylindrical processes, each of 

 which is provided with a multiporous rosette-plate. The ooecia free; sessile avi- 

 ciilaria; the colony attached by radical fibres, which issue from the basal wall 

 of the individual zocEcia. From the proximal portion of the avicularium rises a 

 hollow spine, which as a rule is strongly branched and may cover over a larger 

 or smaller part of the frontal membrane. 



H. radicifera (Hincks). 



Membranipora radicifera, Hincks, Annals nat. hist. 5 S. 



Vol. 8, 1881, pag. 5, PI. 2, figs. 6, 6 a, 6 b. 



(PI. IV, figs. 6a-6c). 



The zooecia are broad, hexagonally rounded, with two short, blunt spines 

 and a little further proximally on one, generally the left, lateral margin with a 

 short bifurcated spine with two unequally long branches. The strongly arched 

 basal surface runs out into six, a little lower placed, but also arched, somewhat 

 broad and short tubes which are separated by broad and deep pit-like depres- 

 sions and meet with corresponding processes from the neighbouring zooecia. At 

 the bottom of each pit is an oval hole, which opens on the frontal surface of 

 the colony, but on account of the somewhat imbricate position of the zocecia, 

 these holes are not very distinct. They open on each side of the distal end of the 

 zocecium. Each tube is furnished with a large, multiporous, strongly calcified 

 rosette-plate, occupying the whole of its breadth, and the arched basal surface 

 of each zocecium is furnished with 4 — 6 uniporous rosette-plates, which serve 

 for connection with the numerous radical fibres, by the aid of which the colony 

 is attached to its underlayer. 



The avicularia are large, proximally furnished with a small, curved spine, 

 and provided with a mandible, which is inclined to one side. Each zocecium 

 has such an avicularium attached along the one lateral margin and directed 

 obliquely inwards, opposite the above-mentioned bifurcated spine. 



The ooecia, which Hincks does not mention, are free, widest at the proxi- 

 mal end, cup-shaped or semi-conical, furnished with an obliquely ascending 



^ ni, p. 16, ^ 75, p. 22, 76, pp. 60 — 61. 



