14 BULLETIN 112, UNITED STATES NATIONAL MUSEUM. 
Section YOLDIELLA Verrill, 1897. 
YOLDIA SILIQUA Reeve, 1855. 
Last of the Arctic Voy., vol. 2, p. 396, pi. 33, fig. 3. 
Norton Sound, Alaska. Also Atlantic. 
YOLDIA INTERMEDIA Sars, 1865. 
Fos. Dyre. Quatern. period, p. 38, figs. 92. 96. 
Bering Strait and Norton Sound. Circumboreal. 
YOLDIA ORCIA Dali, 1916. 
Proc. U. S. Nat. Mus., vol. 52, No. 2183, p. 399. 
Tillamook Bay, Oregon, to San Diego. 
YOLDIA SANESIA Dali, 1916. 
Proc. U. S. Nat. Mus., vol. 52, No. 2183, p. 399. 
Boca do Quadra, Alaska, to Point Conception, California. 
YOLDIA OLEACINA Dali, 1916. 
Proc. U. S. Nat. Mus., vol. 52, No. 2183, p. 398. 
Arctic Ocean north of Bering Strait. 
YOLDIA CAPSA Dali, 1918. 
Proc. U. S. Nat. Mus., vol. 52, No. 2183, p. 400. 
Off Tillamook Bay, Oregon, in 786 fathoms. 
YOLDIA CECINELLA Dali, 1916. 
Proc. U. S. Nat. Mus., vol. 52, No. 2183, p. 399. 
Aleutian Islands to Gulf of California. 
Genus PLEURODON Wood, 1840. 
Subgenus Cyrtlla A. Adams, 1860. 
CYRILLA MUNITA (Carpenter) Dail, 1898. 
Trans. Wagner Inst., vol. 3, pt. 4, p. 602. 
Santa Barbara Islands, to Gulf of California. 
Genus MALLETIA Desmoulins, 1832. 
MALLETIA TALAMA Dali, 1916. 
Proc. U. S..Nat. Mus., vol. 52, No. 2183, p. 400. 
Bering Sea to Oregon. 
MALLETIA PACIFICA Dali, 1897. 
Bull. Nat. Hist. Soc. Brit. Col., No. 2, p. 11, pi. 2, fig. 11. 
Chignik Bay, Alaska, to Monterey, California. ^^5 ^ 
MALLETIA FABA Dali, 1897. 
Bull. Nat. Hist. Soc. Brit. Col., No. 2, p. 10, pi. 2, fig. 10. 
Queen Charlotte Islands, British Columbia, to Lower California. 
MALLETIA FIORA Dali, 1916. 
Proc. U. S. Nat. Mus., vol. 52, No. 2183, p. 400. 
Off Sitka, Alaska, 1,569 fathoms. 
