The small bivalve, Florida lyonsia, Lyonsia floridana Conrad, 1849, can be abundant at University Beach, Corpus Christi Bay, Texas. Most shells are usually quite small and fragile, but it can reach up to 18 mm long (3/4 in). The animal attaches sand grains to its periostracum. The shell is thin and translucent, elongate-oval, with fine radial lines crossed by comarginal growth lines. The anterior end of the shell is rounded and the posterior is elongated and tapers until it ends abruptly.

This species is found in bays and shallow Gulf waters from 0 to 7 m (23 ft). It is distributed from Texas to Florida. The related species, Lyonsia hyalina is considered either a subspsecies or a synonym by some authors.

Read more about this species in Tunnell et al (2010)’s Encyclopedia of Texas Seashells, page 336.