Micrographs of adult females of Profilicollis altmani from Larus belcheri, on the Peruvian coastline, Lima. 23. Lateral view of trunk spines showing their single drop-shaped core support structure. 24. Anterior end of a specimen showing the 2 lateral retinacular nerves (arrow), the proboscis receptacle (PR) and a lemniscus (L). 25. Anterior trunk showing the prominent branching longitudinal muscle fibers and the hypodermic nucleated cells in the area of the fibrillar attachment of a lemniscus (L) to the body wall. 26. Posterior part of a female reproductive system showing the near terminal position of the gonopore and the characteristic 4 horizontal nucleated cells at the posterior end of the vagina and between the sphincters (arrows). 27. Simple, thin-walled uterine bell with few small nucleated uterine bell cells (arrows). Note part of the reticular lacunar system (left) and median ligaments. 28. Eggs. Note the thick outer shell and the polar prolongation of the fertilization membrane.