D.P. GORDON AND P.D. TAYLOR 
Figs 55-59 Onychocellid cheilostomes. 55-56, Ogiva incompta sp. noy., IGNS BZ 189-2, paratype, neanic colony showing disposition of autozooids 
and vicarious avicularia, x 51 and x 84 respectively. 57-59, Onychocella? lamellosa sp. nov., IGNS BZ 190, holotype; 57, autozooids and avicularium, x 
58; 58, close-up of avicularium, x 129; 59, zooid with entrance to concealed ovicell, x 109. 
subvicarious, occurring sporadically at the bifurcation of zooid rows 
but not every new zooid row starts with an avicularium; 0.65—0.71 
mm long and 0.35—0.45 mm wide, the acute rostral tip overlaps the 
proximal end of the distal autozooid, making that end W-instead of 
V-shaped; rostral foramen subtriangular, bordered proximally by a 
stout pair of ridge-like pivots that do not fuse medially to form a 
cross-bar; no opesial foramen. Ovicells immersed under the 
cryptocyst of the succeeding zooid, visible as a slight bulge, with a 
narrow transverse opening just distal to the opesia-orifice of the 
maternal zooid. Lateral communication pore areas recessed between 
slight buttresses of inner autozooidal walls. 
REMARKS. The zooidal and especially the opesial characters of 
this species are as much aspidostomatid as onychocellid, and the 
generic and family attributions are uncertain. Nevertheless, it is clear 
from the literature that there has been (and remains) considerable 
difficulty in distinguishing generic and, hence, familial boundaries 
in the large range of fossil species attributed to Onychocella sensu 
