Taxonomical remarks
Pilsbry (1911) pointed out that T. album are morphologicaly close to T. weltnerianum. The author states that the difference between the two species is that plates of T. album are smooth. However, Hoek (1883) noted on "beautiful striation" of the plates under the microscope, that our observations are also confirmed.
Morphological description of T.weltnerianum see Chan et al., 2009, p.122-123, fig.103,104 and the Internet reference
Taxonomic name: