PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 343 



Extra - 1 i m i tal Species. 

 Genus PATELLA Linne. 



Patella Lin. S. N. ed. x, 1758.— Dall, 1. c. p. 266, 1671 (full synonymy). - 

 Patella vulgata. 



P. vulgata Lin. Syst. Nat. ed. sii, p. 1258.— Dall, 1. c. p. 268, pi. 15, f. 23, 1861. 



British and Xorth European seas from the Mediterranean to the 

 Northern Lofoten Islands, between tides. Type of the genus. 



Genus PATENA Leach. 



Patina Leach, MSS. 1819 ; Moll. Gt. Brit. 1852, p. 223.— Dall, 1. c. p. 279. 



Helcion Jeffreys, not Montfort. 



Nacella H. & A. Adams, Sars, not Schumacher. 



Patina pellucida. 



Patella pell ucida Lin. S. N. ed. xii, p. 1260. 



Patina pellucida Leach, 1. c. p. 224, 1852.— Dall, 1. c. p. 280, pi. 16, f. 20, 1871. - 



British and North European seas, northward to Lofoten; in most 

 cases living on the stalks and fronds of large fuci. 

 December 16, 1878. 



LIST OF THE FIGURES. 



Plate I. 



1. Leptocliiton cancellatus Sby., Alaska: a, major lateral from above. 



2. Hanleyia mendicaria Mighels & Adams, Casco Bay, Maine. 



3. Trachydermon ruler Lowe, Greenland: a, major uncinus from below. 



4. Trachydermon albus Lin., Alaska. 



5. Tonicella lineata Wood, Alaska. 



6. T. marmorea Fabr., Greenland. 



7. T. suhmarmorea Midd., Alaska. 



8. ScMzoplax Brandtii Midd., Aleutian Islands. 



9. Chcetopleura gemma Opr., California. 



10. C. ? Hartivegii Cpr., California. 



Plate II. 



11. Maugerella consjricua Cpr., California. 



12. Stcnoradsia magdalenensis Hinds, California. 



13. Stenoplax limaciformis Sby., west coast of Mexico. 



14. Ischnochiton regularis Cpr., California. 



15. Ischnochiton Cooperi Cpr., California. 



16. Ischnochiton interstinctus Grid., Alaska. 



17. Ischnoradsia trifida Cpr., Alaska: a, cusp of major lateral from above. 



18. Lepidopleurus Mertensii Midd., Alaska: a, rhachidian in situ. 



19. Lepidoradsia australis Sby., Port Jackson, Australia. 



20. Callistochiton palmulatus Cpr., California. 



Plate III. 



21. Pallochiton lanuginosus Cpr., California. 



22. Chiton articulatus Sby. : a, side view of rhachidian tooth. 



23. Isehnoplax pectinatus Sby., West Indies. 



