One can imagine the interest and astonishment with which the great Greek would have been filled had some unduly precocious disciple shown to him the red-blood-system of the marine terrestrial Annelids; the red blood of Planorbis, of Apus cancriformis, and of the Mediterranean razor shell, Solen legumen.
It is by the specialization of two " endites " that the endopodite and exopodite of higher Crustacea are formed, whilst a flabelliform exite is the homogen or genetic equivalent of the epipodite (see Lankester, " Observations and Reflections on Apus Cancriformis," Q.
- The second thoracic (fifth post-oral) appendage of the left side of Apus cancriformis, placed with its ventral or neural surface uppermost to compare with figs.
- The first thoracic (fourth post-oral) appendage of Apus cancriformis (right side).
Lankester, " Observations and Reflections on the Appendages and Nervous System of Apus Cancriformis," Quart.