Puellina praecox is an encrusting bryozoan. Colonies form irregular patches, composed of a single layer of autozooids. This species is very small; the largest known specimen consists of approximately 20 autozooids. Autozooids are irregular, oval, convex and clearly separated. They range in size from0.14-0.30 by 0.10-0.19 mm. Five spines are present in non-reproductive zooids, and four in reproductive zooids (with an ovicell).
The species is able to colonise shells and hard substrates. It has been recorded at depths of 73-99 metres. Puellina praecox is found as a fossil in the Pleistocene Red Crag of East Anglia, and is only known as a living bryozoan from a few localities off the English Channel coast of Brittany; from the Irish Seam and off Antrim.
Puellina praecox closely resembles Puellina bifida, however P. praecox is less heavily calcified than P. bifida