PLATE XVI. 



FIG. 



1. ATRACTYLIS ARENOSA, p. 88, nat. size. 



1 a. Ditto, magnified. 1 b. The ovary after the rupture of 



the gonophore. From drawings by the Author. 



2. PERIGONIMUS REPENS, p. 90, on an operculum, nat. size. 



2 . Polypites, magnified. 2 b. The gonozooid, magnified. 



From drawings by Mr. Alder. 



3. PERIGONIMUS SERPENS, p. 95, highly magnified. From 



a drawing by the Author. 



