It may be noted that in all these genera the axial lobe of the pygidium is either short or narrow.
All indications are that the spine was not in any sense a pygidium.
Posterior part of the thorax and pygidium, showing endopodites and exopodites projecting under the dorsal test.
It and the pygidium are due solely to functional requirements.
All are long and heavy, and there seems to be no decrease in size toward the pygidium.
Appendages of the thorax and pygidium, seen from the ventral side.
Of the modification the respiratory apparatus underwent beneath the pygidium, we have no evidence.
The appendages of the thorax and pygidium, seen from the lower side.
A triangular specimen consisting of the greater part of a pygidium and parts of all the thoracic segments.
An exceedingly remarkable organ of sense, which is found in all fleas, is called the pygidium.