Abstract: A semiautomated machine (10) cuts a disk (60a) from the mouth side of sea urchin shells (60) for efficient extraction of gonads, the sea urchin reproductive organs, with minimal damage. The machine is capable of preserving intact the original five segmented star configuration. A conveyor (12) receives and retains sea urchins (60) with the mouth side of the sea urchin shells facing away from the conveyor. A cutter (15) is mounted over the conveyor at a cutting location (16). A relatively thin elongate cutting element (38) is spaced from the conveyor (12) and oriented generally transversely across the conveyor. An extended aligning plane (65,66) parallel to the conveyor is mounted on the opposite side of the elongate cutting element (38) from the conveyor (12) at the cutting location (16). The aligning plane (66) contacts the mouth side of the sea urchin shells and aligns and maintains orientation of the sea urchins with the mouth side of the sea urchin shells facing the aligning plane.