36 BULLETIN 71, UNITED STATES NATIONAL MUSEUM. 



and in Hongkong Harbor. It occurred at Nero station 201 in 1,033 

 fathoms and 209 in 82 fathoms off Midway Islands, station 990 in 

 859 fathoms off Guam, and stations 2031 in 1,624 fathoms, 2036 in 

 82 fathoms, and 2074 in 22 fathoms off the Hawaiian Islands. In the 

 Albatross material it has occurred at H 2922 in 268 fathoms also off 

 the Hawaiian Islands and D 4922 in 60 fathoms and H 4882 in 248 

 fathoms both off Blake Reef, Colnett or Vincennes Strait off southern 

 Japan. This region from other species already recorded here has 

 proved to be southern in its relations and a region at which many 

 southern species seem to approach their northern limits on this coast. 

 This species is used at the present time to include various forms 

 which may be distinct. Brady notes the fact that various forms 

 occur and Bagg also found them. A study of recent tropical mate- 

 rial should show something definite in regard to these specific or 

 varietal forms. 



Genus OPERCULINA d'Orbigny, 1826. 



Nautilus (part) Gronovius, Zooph. Gron., 1781, p. 282. 



Lenticulites (part) Defrance, Diet. Sci. Nat., vol. 25, 1822, p. 453. 



Operculina d'Orbigny (Type, 0. complanata Defrance), Ann. Sci. Nat., vol. 7, 



1826, p. 281.— H. B. Brady, Rep. Voy. Challenger, Zoology, vol. 9, 1884, 



p. 742. 



Description. — Test coiled, compressed, consisting of numerous 

 chambers in three or four volutions, bilaterally symmetrical, and all 

 visible from either side, not embracing, except in the early whorls, 

 in face view very thin, usually thickest at the umbonal region; sur- 

 face smooth or ornamented with bosses; aperture single at the base 

 of the apertural wall of the chamber. 



Carpenter * has given a very detailed account of the structure of 

 this genus. The genus is characteristic, at least in the larger forms, 

 of the warmer shallow seas. It is a characteristic genus of the earlier 

 Tertiaries. 



OPERCULINA COMPLANATA (Defrance). 



Lenticulites complanata Defrance, Diet. Sci. Nat., vol. 25, 1822, p. 453. 



Operculina complanata d'Orbigny, Ann. Sci. Nat., vol. 7, 1826, p. 281, pi. 14, 

 figs. 7-10; Modeles, No. 80. — Parker and Jones, Ann. Mag. Nat. Hist., 

 ser. 3, vol. 8, 1861, p. 229.— H. B. Brady, Rep. Voy. Challenger, Zoology, 

 vol. 9, 1884, p. 743, pi. 112, figs. 3, 4, 5, 8.— Woodward and Thomas, 13th 

 Ann. Rep. Geol. Nat. Hist. Surv. Minnesota for 1884 (1885), p. 175, pi. 4, 

 fig. 35; vol. 3, 1893, p. 45, pi. E, fig. 37.— [?] Egger, Abh. kon. bay. Akad. 

 Wiss. Miinchen, CI. n, vol. 18, 1893, p. 435, pi. 20, figs. 40-42.— Newton and 

 Holland, Journ. Coll. Sci. Imp. Univ. Tokyo, 1902, p. 13, pi. 1, fig. 3, 5; 

 pi. 3, fig. 3.— Millett, Journ. Roy. Micr. Soc, 1904, p. 605. 



Description. — Test much compressed, the early volutions somewhat 

 embracing, later ones nonembracing, bilaterally symmetrical, cham- 



1 Introd. Foram., 1862. 



