14 
D.P. GORDON AND P.D. TAYLOR 
Figs 30-31 Jmmergentia sp., NHM BZ 206. 30, portion of surface of eroded molluscan shell with bryozoan borings, x 39. 31, close-up of borings made 
by three autozooids; furrows indicating some of the traces of former principal stolons (ps) and adventitious stolons (as) are labelled, x 109. 
of the Neogene to the present day. Three other boring ctenostome 
genera (Pohowsky 1978) have been accorded ranges coinciding 
with the age of the Red Bluff Tuff — these are Orbignyopora 
Pohowsky (?Silurian-Pliocene), Penetrantia Silén (?Lower Creta- 
ceous-Recent), and Spathipora Fischer (nominally Jurassic- 
Recent, but the age and precise characters of the type species are 
uncertain). Orbignyopora can be discounted as a name for the Red 
Bluff Tuff specimen in that the zooids, although ‘non-pedunculate’ 
like Immergentia (i.e., separated from the principal stolon by a 
short connecting stolon), are disposed horizontally immediately 
beneath the shell surface. Penetrantia zooids are pedunculate, so 
this genus, otherwise common in the New Zealand Neogene, can 
also be ruled out. Spathipora, as understood, is also pedunculate 
and has never been recorded from the New Zealand region. No 
other genus of boring ctenostome accords with the characters of 
the form from Red Bluff Tuff and we are confident that the charac- 
ters of the borings in the specimens correlate with the characters 
of Immergentia. We do not ascribe a species name to these borings, 
however, inasmuch as most of them are sediment-infilled, preclud- 
ing polyester-resin casting which provides many more characters 
than are presently determinable. 
Order CHEILOSTOMATA Busk, 1852 
Suborder FLUSTRINA Smitt, 1868 
REMARKS. Smitt’s suborder included the families Flustridae, 
Cellariidae, and Membraniporidae (sensu lato, comprising later 
calloporids, chaperiids, etc.) but excluded many “cellularine anascans’ 
like Aetea, Eucratea, Bugula, etc. It is used here as an available 
taxon in a historically significant work (see Schopf & Bassett, 1973) 
in preference to Neocheilostomina d’Hondt (1985) which also 
included ascophorans. 
Family CALLOPORIDAE Norman, 1903 
Genus FLUSTRELLARIA @ Orbigny, 1853 
TYPE SPECIES. Flustrellaria fragilis d Orbigny, 1853; by subse- 
quent designation of Bassler (1935); Cenomanian, LeMans, France. 
REMARKS. According to the taxonomic criteria used by 
d’Orbigny (1851-54), based on colonial and zooidal characters, 
Flustrellaria was established for membraniporiform unilaminate 
fragments whose zooids lacked frontal ‘pores’ (i.e., adventitious 
avicularia). The first-named species, selected as type by Bassler 
(1935), was F. fragilis, based on unattached fragments. According 
to the illustrations of this species (d’ Orbigny 1853, pl. 723, figs 5— 
9) there is a large, rimmed opesia occupying most of the zooidal 
length, with a small to vestigial gymnocyst, and a dependent 
prominent hyperstomial ovicell apparently not closed by the 
zooidal operculum in life. Oral and marginal spine bases were not 
illustrated, but according to Canu (1900: 372) there are 8-10 spine 
bases in the specimen he examined from the d’Orbigny Collec- 
tion, and spine bases are visible in photographs of the type and 
another specimen loaned by Prof. E. Voigt. A similar, shell-en- 
crusting species, Flustrellaria ornata d’Orbigny, 1853 was 
illustrated with marginal spines (d’Orbigny 1853, pl. 728, figs 11, 
12). This was chosen as the type species of Ornatella Canu, 1900, 
a new subgenus of Membranipora de Blainville. D’Orbigny’s reli- 
ance on colonial characters, frequently superficial, was rejected by 
most late nineteenth- and early twenteeth-century bryozoologists 
including Canu, and Flustrellaria and related genera were rel- 
egated to Membranipora, ironically already a very heterogeneous 
taxon as then used. Accordingly, Flustrellaria has been scarcely 
used as a genus, although it was listed by Bassler (1935, 1953), 
who cited Ornatella as a junior subjective synonym. 
It appears possible to use Flustrellaria as a valid genus, although 
SEM examination of d’Orbigny’s material is desirable in order to 
