SEM of cystacanths of Profilicollis altmani from Emerita analoga on the Peruvian coastline, Lima. 5. A robust hook in the mid-section of a proboscis with thick base. 6. The posterior part of the neck interface with the anterior spinose trunk of a cystacanth. Note anterior spines in perfect ring (arrow). 7. The posterior part of anterior trunk section showing the incomplete spination posteriorly (arrow). 8. More posterior trunk spines are occasionally in irregular circles randomly distributed. 9. A high magnification of a trunk spine showing cross serrations of cuticular surface. 10. A Gallium cut section of a trunk spine showing its spongy center and denser cortical layer.