SOME POLYCLADS OF THE NEW ENGLAND COAST, ESPECIALLY OF THE WOODS HOLE REGION

¹ From the American Museum of Natural History, New York City

1. Stylochus zebra (Verrill) 1882 is shown to have been correctly placed by Verrill in the genus Stylochus.

2. Eustylochus ellipticus (Girard) 1850 is shown to be a typical member of the genus Stylochus, its name thus becomes Stylochus ellipticus, and Eustylochus becomes a synonym of Stylochus.

3. Notoplana atomata, usually erroneously called Leptoplana variabilis, is the most common polyclad of the Maine coast.

4. Prosthiostomum gracile Girard 1850 has been rediscovered at Woods Hole. The later name Euplana gracilis which Girard gave to this species is valid and Discoplana Bock 1913 becomes a synonym of Euplana Girard 1893.

5. Specimens of Leptoplana angusta Verrill 1892 have been found at the Peabody Museum, Yale University. The species is placed in the genus Stylochoplana although it differs somewhat from the typical members of the genus. The name is then Stylochoplana angusta (Verrill).

6. As noted by Bock (1913), Planocera inquilina Wheeler 1894 must be transferred to the genus Hoploplana and the correct name of the species is Hoploplana inquilina. What Wheeler considered to be the penis is in reality the prostatic vesicle.

7. Two common and well-known Sargassum polyclads have been taken on the Sargassum in Vineyard Sound; these are Hoploplana grubei (Graff) 1892 and Gnesioceros sargassicola (Mertens) 1833. Pelagoplana Bock 1913 becomes a synonym of Gnesioceros Diesing 1861.

8. Another species of Gnesioceros, G. verrilli, new name, occurs around Woods Hole; it was seen by Verrill in 1882 and erroneously identified by him as Imogine oculifera.

9. A single specimen of Eurylepta maculosa Verrill 1892 was found at the Peabody Museum; some details of its anatomy are described.