BRYOZOANS FROM CHATHAM ISLAND 
ovicells. When definite ovicells are discovered in C. fossilis they 
should clarify the taxonomic position of this species. 
Genus OGIVA Jullien, 1882 
TYPE SPECIES. Eschara actaea d’Orbigny, 1851; by original 
designation; Coniacian, Fécamp, France. 
REMARKS. Originating in the Cenomanian (Taylor, 1993), the 
family Onychocellidae is especially well represented in the Late 
Cretaceous by a bewildering number of species whose colonial, 
autozooidal, and avicularian characters seem to intergrade to such an 
extent as to defy clear circumscription into genera. Such is also the 
case among the Cenozoic forms which are, however, relatively less 
diverse. In his voluminous work on the Cretaceous bryozoan faunas 
of France, d’Orbigny (1851-54) distributed the species, among 
which are encrusting, branching-cylindrical. and bilamellar forms, 
between several ‘form-genera’ based on colonial morphology. As 
Canu (1900) pointed out in his revision of this work, d’Orbigny 
often failed to account for ontogenetic variation in the appearance of 
zooids, and the illustrations accompanying the descriptions were 
often inexact, so that both he and Pergens (1889), who had attempted 
to revise the cyclostomes, frequently had difficulty in matching 
illustrations with specimens. 
Jullien (1882) introduced the family Onychocellidae, the genera 
Onychocella, Ogivalina, Floridina, and Smittipora with Recent type 
species, and four other genera (Ogiva, Dictuonia, Collura, and 
Rhebasia) based on d’Orbigny species. The genera were 
distinguished, not primarily by colonial morphology, but by zooidal, 
opesial, and avicularian characters. A few years later, Koschinsky 
(1885) added Rhagasostoma, with an Eocene type species. Canu 
(1900) merged Dictuonia, Collura, and Rhebasia in Ogiva (which 
has page priority in Jullien 1882) on the grounds that the range of 
zooidal morphologies represented by these genera varies according 
to the ontogenetic age of the zooid and more than one such morphol- 
ogy can occur in the same colony — ‘La forme colluréenne est 
toujours un signe de vieillesse; une ogivalia passe rapidement soit en 
dictuonia soit en rhebasia; c’est encore un signe de vieillesse. Les 
formes dictuonienne ou rhébasienne envahissent parfois tellement 
une espéce que la forme ogivalienne jeune est trés rare’ (Canu 1900: 
387-388). Complicating an appreciation of the validity of the four 
Jullien genera based on species of d’Orbigny (1851) (and which 
influenced Canu’s conclusions) is a lack of definitive knowledge of 
those species. Eschara aceste (type species of Dictuonia) was 
lacking from the collection when Canu revised it, and the specimen 
and illustrations of E. actaea (type species of Ogiva) did not 
correspond (Canu 1900: 420); E. dorilas (type species of Rhebasia) 
and E. athulia (type species of Collura) were represented by worn 
specimens only. A thorough revision of the d’Orbigny collection 
using scanning electron microscopy of all available material is 
critically needed. Pending such a revision, and its impact on the 
classification of onychocellids, the genus name Ogiva is used here 
for the following new species. 
Ogiva incompta sp. nov. Figs 53-56 
IGNS BZ 189-1, from Pukekio, Chatham Island. 
IGNS BZ 189-2. 
HOLOTYPE. 
PARATYPE. 
NAME. From the Latin, incomptus, unadorned, referring the plain 
appearance of the zooids. 
DESCRIPTION. Colony erect, comprising narrow to moderately 
wide bilamellar stems that broaden, in the two fragments available, 
23 
from 1.08 mm diameter to 3.70 mm wide. Autozooids generally 
‘dictuonian’, 1.e., regularly 4-sided, alternating and arranged very 
evenly in oblique rows in the narrow-based fragment; most zooids 
very slightly rounded at distal and proximal ends, with some drawn 
out proximally and approaching the ‘rhebasian’ form in the broader, 
more worn fragment; length = 0.41—-0.65 mm, width = 0.33-0.43 
mm. Zooidal boundaries marked by a shallow but distinct furrow, 
the cryptocyst neither smooth nor granular in the present material, 
sloping inwards on all sides to the more-or-less centrally placed 
circular to subcircular opesiae (0.14—0.19 mm long, 0.14—0.17 mm 
wide). No spine bases or other features. Avicularia vicarious, per- 
fectly replacing autozooids in a series without disrupting the 
regularity of oblique rows, almost identical to autozooids in appear- 
ance and width (0.31—0.37 mm) but distinguished from them by: (1) 
their slightly greater relative length within rows (0.54—0.77 mm) 
such that the acute rostral tip overlaps the proximal end of the distal 
autozooid, making that end W- instead of V-shaped; and (2) a more 
longitudinally oval opesiae (0.18—0.22 mm long, 0.11—0.14 mm 
wide). Lateral margins of colony comprising both autozooids and 
avicularia. No enlarged brooding or ovicelled zooids seen. 
REMARKS. Although differing in size, the two fragments are suffi- 
ciently alike in zooidal characters to be considered as conspecific. 
The smaller, paratype fragment (Fig. 55) has an almost circular 
diameter proximally, broadening to bilamellar distally, with slightly 
smaller zooidal dimensions overall than the larger, holotype frag- 
ment (Fig. 53), which being broader and therefore certainly more 
distal in a colony would be expected to have incrementally larger 
zooid sizes. The larger fragment also lacks lateral margins so would 
have been broader in life than its current maximum breadth of 3.70 
mm. 
Brown (1958), without comment on the status of the genus, 
attributed two Tertiary Victorian species to Ogiva: Membranipora 
concamerata Waters, 1881 (Janjukian-Balcombian = Chattian- 
Langhian) and Omoiosia elongata Canu & Bassler, 1935 
(Balcombian). The former species has slender, cylindrical branch- 
ing stems and may represent a new genus of Onychocellidae; the 
latter species is definitely congeneric with O. inornata, from which 
it differs in having more longitudinally oval opesiae set in the distal 
half of the cryptocyst. (Based on the type species, Omoiosia Canu & 
Bassler, 1927, is, as Brown (1958) pointed out, a junior subjective 
synonym of Chaperia Jullien, 1881.) 
Genus ONYCHOCELLA Jullien, 1882 
TYPE SPECIES. Onychocella marioni Jullien, 1882, by original 
designation; Recent, Cape Verde Islands to France and the Mediter- 
ranean, = Cellepora angulosa Reuss, 1848; Badenian (Langhian- 
Serravallian), NuBdorf, Austria (see Harmer 1926). 
Onychocella? lamellosa sp. nov. Figs 57-59 
HoLotyPe. IGNS BZ 190, from Pukekio, Chatham Island. 
NAME. From the Latin /amella, a thin plate, veneer, alluding to the 
layered nature of the colony from self-overgrowth. 
DESCRIPTION. Colony encrusting, self-overgrowing. Autozooids 
arranged quincuncially, sometimes almost as broad as long, length = 
0.65—0.84 mm, width = 0.43—0.65 mm, with the lateral margins and 
especially the distal rim thickened and raised. Frontal cryptocyst 
granular, the opesia-orifice wider (0.21—0.26 mm) than long, the 
proximal rim broadly and narrowly anvil-like and slightly upturned, 
with rounded opesiular indentations at the corners. Avicularium 
