Scale bar = 10 micrometers.

Specimen morphology closely resembles the illustration published in Patrick & Reimer 1966, however this illustration lacks the lunate process present in the Texas specimens. Kramer & Lange-Bertalot published a photo of a Caloneis closely resembling the Texas specimen, page 787, fig. 5, described as C. schumanniana. There appears to be a great deal of variability within each species in the genus, and the identity of specimens of Caloneis has been debated. After much deliberation I have concluded that the Texas specimens most closely fit the illustration and description of C. ventricosa by Patrick & Reimer.