Cribrilina punctata (Hassall, 1841)
Colonies are encrusting, multiserial, sheet-like, with up to 500 zooids. Approximately eight distolateral pore chambers per zooid may be visible in abraded colonies and at growing edges. The ancestrula is tatiform with 13 spines.
Autozooids are moderately small, 0.44-0.62 mm long by 0.26-0.39 mm wide, and roughly elongate ovoidal in outline shape. The gymnocyst is normally not visible. The gently convex frontal shield is formed by 6-14 costae (including the apertural bar), linked by stout lateral costal fusions and united at the centre of the frontal shield. Intercostal pores number 2-4 and each costa has 0-2 lumen pores. The thick apertural bar is prolonged into an acute median mucro, with one or two lumen pores on the proximal side. The orifice is D-shaped, broader than long, with 4 oral spines in non-ovicellate zooids reduced to 2 in ovicellate zooids. Ovicells are globose with a porous ectooecium but without umbones ridges or tubercles.
Avicularia are adventitious, paired on either side of the orifice (though sometimes lacking on one or both sides), originating at the proximolateral corners and directed distolaterally (occasionally laterally), with a short triangular rostrum, a rounded proximal end, and an uncalcified pivotal bar.
Among the five species of Cribrilina recognized by Bishop (1994) in the East Anglian Crags, C. punctata (Hassall, 1841) can be distinguished by the presence of 4 oral spines in non-ovicellate autozooids and the porous ovicell.
Early Pleistocene, Norwich Crag Formation, Covehithe, Suffolk, UK. Also recorded by Bishop (1994, p. 226) from Recent localities on both sides of the North Atlantic, including Scotland, the Isle of Man, Devon, Galway, the Gulf of St Lawrence (Canada), and Nantucket, Massachusetts, USA.