"Micropora brevissima sp. nov.
(Pl. II, figs. 7a-c)
Zoarium incrusting. Zooecia broadly ovate, with distinct raised margins, but there are no lateral « knobs », surface minutely granular and punctate, an elongate foramen on each side a little below the oral aperture ; the oral aperture is very wide and short, directed fonvards rather than upwards. One small triangular avicularium (683) above the orifice has been found, but they are usually absent, though from Cape Horn they occur frequently. Ovicell globular, raised, smooth or slightly granular, and the ovicelligerous zooecia are the same size as the other zooecia. There are pore chambers round the zooecia, about six lateral ones on each side and one distal. There are two oral spines, only seen however on the terminal zooecia.
This differs from M. coriacea Esper, in having the oral aperture very wide and short, in the absence of « knobs », and of the projection on the ovicell, though a trace of this can sometimes be seen. The mandibles, as prepared from Cape Horn material, are about double the size of those of M. coriacea and of the same type although there are minor differences. It much resembles M. perforata MacG., in shape and other respects, but the operculum is wider and shorter, perhaps they should be considered varieties.
In M. stenostoma Busk the ovicelligerous zooecia are much larger than the others, whereas in M. coriacea and M. brevissima they are the same size.
The Escharina peruviana d'Orb. is probably M. perforata MacG.
HABITAT. - Cape Horn, and apparently from New Zealand.
Exp. Antarct. Belge.
No 288 on stones, dry, Dredge I. Lat. 71º 09' S.- Long. 89º 15' W.; 460 met.; +0.3 C.
Nos 591, 596, Tangles VII. Lat. 70º 23' S.- Long. 82º 47' W.; 480 met.; +0.8 C.
Nos 619, 683, Tangles VIII. Lat. 70º 00' S.- Long. 80º 48' W.; 500 ? met.; +0.9 C.
No 820, Tangles X. Lat. 70º 15' S.- Long. 84º 06' W.; 569 met.; +0.8 C.
The geographical distribution of Micropora would seem to be
Northern : M. (Cellaria) borealis Busk ; M. coriacea Esp.
Mediterranean : M. coriacea Esp., M. impressa Moll.
N. Atlantic : M. coriacea Esp.
S. Atlantic : M. uncifera B., M. coriacea Esp.
Australasian : M. uncifera B., M. impressa Moll. (A. W. W. coll.). M. elongata Hincks, M. perforata MacG.
S. Indian Ocean : M. coriacea Esp.
N. Pacific : M. borealis B.
S. Pacific : M. perforata Mac G., as peruviana d'Orb.
S. American : M. uncifera B., M. brevissima nov.
Antarctic : M. coriacea Esp., M. brevissima nov." (Waters, 1904: 40)
