Turbellarian taxonomic database

Abstract / Notes

Morphological and physiological studies were made of specimens of Typhoplana collected at Gettysburg,
Pennsylvania and Mountain Lake, Virginia with the purpose of determining differences between them.
Structurally the two differed in that the former possess a common genital atrium for reception of the sex
products of both sexes, while the latter have a dorsal atrium into which the penis opens and a ventral atrium
which receives the eggs. Also in the former, nerve III emerges from the brain posterior to the dorsal
commissure while in the latter the same nerve emerges anterior to the commissure. Functionally, the
Gettysburg specimens reproduce viviparously during the summer months, the young consuming the viscera of the
mother as they develop, while the Mountain Lake specimens produce hard-shelled eggs through the whole season,
the eggs hatching after laying. On the basis of the evidence the Gettysburg specimens are Typhloplana minima
while the Mountain Lake specimens are Typhloplana viridata but designated as a new sub-species, ovipara,
since they have no viviparous stage of reproduction. This corrects a view held for some time that there is
only one species of the genus Typhloplana.

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