N0.1177. NORTH AMERICAN LEPTONACEA—DALL. 881 



Genus MYSELLA Angas. 



Tellimya Carpenter, 1864, not Brown, 1827; MontaciUa Verrill and Bush, 1898, 

 not Turtou, 1822. 



18. Mysella tumida Carpenter, 1864; Alaska Peninsula and south to 



San Diego, California. 



Described as Tellimya. 



19. Mysella planata DalL 18S5 ', Bering Strait south to the Aleutians 



and east to the Shuiuagin Islands, Maska. 



20. Mysella aleutica Dall, 1899 ; Bering Sea, the Aleutians, aud east to 



Sitka Bay, Alaska. 



21. Mysella pedroana Dall, 1899; San Pedro, California. 



22. Mysella Clementina Cari^enter J 1857; Mazatlan. 

 Described as Lepton. 



23. Mysella diona^a Carpenter, 1857 ; Mazatlan. 

 Described as Lepton. 



24. Mysella obtusa Carpenter, 1865; Mazatlan. 



Described as Moniaciita. 



25. Mysella chalcedonica Carpenter, 1857 ; Mazatlan. 

 Described as Montacuta. 



26. Mysella elliptica Ca>r\)enter, 1857 ; Mazatlan. 

 Described as Montacuta. 



26a. '^.Mysella s%ibqiiadrata Carpenter, 1857 ; Mazatlan. 



Described as Montacuta, said by Carpenter to be congeneric with the two preced- 

 ing species, but his drawing of the hinge looks like Erycina. 



27. Bfysella {Pythinella) sublcevis Car\)enter, 1851 ; Mazatlan. 

 Described as Pyfliina. 



Genus LAS^^A Leach. 



28. Lascea rubra (Montagu), 1804; Puget Sound south to San Diego, 



California; North Atlantic, etc. 



The West American specimens can not be distinguished froril those of Europe. 

 A variety, subviridis Carpenter, is pale greenish yellow. It is reported from 

 Lower California. 



29. Lascea obloiiga C2bV])euter, 1857 ; Mazatlan. 

 ."JO. Lascea trigonalis Carpenter, 1857 ; Mazatlan. 



This and the preceding species need more thorough study. 



Genus TURTONIA Alder. 



31. Turtonia minuta Fabricius; Bering Sea to the Shuiuagins. 

 Precisely similar to European and New England specimens. 



32. Turtonia occidentalis Dall, 1871; Plover Bay, Bering Strait, and 



northward, in 20 to 40 fathoms. 



Larger, stouter, and shorter than the preceding 

 Proc. N. M. vol. xxi 56 



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