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638 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 14
ern California, 45 fms. One of the latter is almost exactly like the
type specimen except that the ovicell encloses three peristomes. The
other colony differs only in having the 3 or 4 marginal rows of peristomes
suddenly much elevated.
Plagioecia ambigua new species
Plate 66, fig. 8
The zoarium is flat and thin, entirely adnate, encrusting the smooth
surface of a shell. The proximal portion is narrowly flabellate, with a
very simple ovicell; beyond this the zoarium becomes broadly flabellate
with a similar simple ovicell at one side and a very broad ovicell occupying much of the width of the lobe. The zooecial tubes are elongate,
moderately distinct on the surface, slightly cross-striated and perforated
with small pores, 0.20 mm in width. The peristomes are only suberect
and directed strongly forward, the diameter 0.15 and the round aperture
0.13 mm; arranged in quincunx. There is only a single row of incomplete tubules at the margin.
The simple proximal ovicell is about 0.40 mm in width by 0.75 mm
long; the simple lateral ovicell 0.30 mm wide by 0.70 mm long and the
large ovicell is about 1.60 mm broad by 0.80 mm long. The ooeciostome
is terminal in the small ovicells, erect at the proximal side of a peristome;
in the large ovicell the ooeciostome is similarly situated, but is somewhat
subterminal as the ooecial cavity has extended slightly beyond it; diameter
of aperture 0.08 mm.
Type, U. S. Nat. Mus. no. 11049.
Type locality, Point Barrow, Alaska, 130 feet, Arctic Research Laboratory, G. E. MacGinitie, collector, one colony.
This is a very unusual specimen, with characters of several genera.
There are two simple ovicells like slightly expanded zooecial tubules
and with terminal ooeciostomes, much like Oncousoecia diastoporides,
except that the ooeciostome is associated with a peristome. There is also
a much expanded ovicell, transverse, surrounding several peristomes,
with a subterminal ooeciostome and resembling Plagioecia, except for
the position of the ooeciostome proximal to a peristome. The latter
character is more like that of Tubulipora. The ovicell surrounds a number of peristomes, which would place the species under Diaperoecia.
With such a combination of characters, one is naturally in doubt as
to the generic relationship, but I am accepting as the most important
character the fullest development of the ovicell, expanded laterally and
with a subterminal, median ooeciostome.
Object Description
Description
| Title | AHF-PUB-PE-14-03~028 |
| Format (imt) | image/tiff |
| Contributing entity | University of Southern California |
| Filename | AHF-PUB-PE-14-03~028.tiff |
| Full text | 638 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 14 ern California, 45 fms. One of the latter is almost exactly like the type specimen except that the ovicell encloses three peristomes. The other colony differs only in having the 3 or 4 marginal rows of peristomes suddenly much elevated. Plagioecia ambigua new species Plate 66, fig. 8 The zoarium is flat and thin, entirely adnate, encrusting the smooth surface of a shell. The proximal portion is narrowly flabellate, with a very simple ovicell; beyond this the zoarium becomes broadly flabellate with a similar simple ovicell at one side and a very broad ovicell occupying much of the width of the lobe. The zooecial tubes are elongate, moderately distinct on the surface, slightly cross-striated and perforated with small pores, 0.20 mm in width. The peristomes are only suberect and directed strongly forward, the diameter 0.15 and the round aperture 0.13 mm; arranged in quincunx. There is only a single row of incomplete tubules at the margin. The simple proximal ovicell is about 0.40 mm in width by 0.75 mm long; the simple lateral ovicell 0.30 mm wide by 0.70 mm long and the large ovicell is about 1.60 mm broad by 0.80 mm long. The ooeciostome is terminal in the small ovicells, erect at the proximal side of a peristome; in the large ovicell the ooeciostome is similarly situated, but is somewhat subterminal as the ooecial cavity has extended slightly beyond it; diameter of aperture 0.08 mm. Type, U. S. Nat. Mus. no. 11049. Type locality, Point Barrow, Alaska, 130 feet, Arctic Research Laboratory, G. E. MacGinitie, collector, one colony. This is a very unusual specimen, with characters of several genera. There are two simple ovicells like slightly expanded zooecial tubules and with terminal ooeciostomes, much like Oncousoecia diastoporides, except that the ooeciostome is associated with a peristome. There is also a much expanded ovicell, transverse, surrounding several peristomes, with a subterminal ooeciostome and resembling Plagioecia, except for the position of the ooeciostome proximal to a peristome. The latter character is more like that of Tubulipora. The ovicell surrounds a number of peristomes, which would place the species under Diaperoecia. With such a combination of characters, one is naturally in doubt as to the generic relationship, but I am accepting as the most important character the fullest development of the ovicell, expanded laterally and with a subterminal, median ooeciostome. |
| Archival file | hancockunpub_Volume21/AHF-PUB-PE-14-03~028.tiff |
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