122 BULLETIN- 104, UNITED STATES NATIONAL, MUSEUM, 



some species that can be identified with it in the region from which 

 it was described can later be definitely placed, 



Subfamily 5. Cassidulininae. 



This subfamily includes forms which are peculiarly constructed in 

 that there is a combination of two distinct modes of growth. One of 

 these, so usual in this family, is the biserial, which is here combined 

 with a spiral or volute method. The combination of the two makes 

 a complex test. 



Two genera are common in the Atlantic, Cassidulina and Ehren- 

 hergina, both of which are represented by several species. 



Genus CASSIDULINA d'Orbigny, 1826. 



Cassidulina d'Orbigny (type, C. laevigata d'Orbigny), Ann. Sci. Nat., vol. 7, 

 1826, p. 282.— H. B. Brady, Rep. Voy. Cliallengcr, Zoology, vol. 9, 1884, p. 

 427.— Chapman, The Foraminifera, 1902, p. 175.— Cushman, Bull. 71, U. S. 

 Nat. Mus.,pt. 2, 1911, p. 95. 



Bxirseolina Seguenza, Atti Accad. Lincei, ser. 3, vol. 6, 1880, p. 138. 



Description. — Text complex, at least the early portion coiled, the 

 chambers arranged biserially, alternating on the sides of the axis of 

 coiling, chambers usually extending to the unbilicus on the sides, in 

 some species the later portion of the test uncoiling; wall calcareous, per- 

 forate, usually smooth and without ornamentation; chambers nu- 

 merous, the sutures usually distinct; aperture looplike, modified in 

 breadth and length in the different species. 



D'Orbigny's original description of the genus, while not complete, 

 is, with the figure and model of C. laevigata, the type species, very 

 clear. 



Its relation to Spiroplecta is really close, the biserial chambers be- 

 ing placed alternately on the sides of the axis of coiling instead of 

 forming a linear biserial series. 



In the present-day oceans the genus is widely distributed and is 

 one of those which extends into the very cold waters of the polar 

 regions. 



From the records it is mostly known as a fossil from the Tertiary 

 but according to Chapman extends back to the Lower Cretaceous. 



CASSroULINA laevigata d'Orbigny. 



Plate 24, fig. 4. 



Cassidulina laevigata d'Orbigny, Ann. Sci. Nat., vol. 7, 1826, p. 282, pi. 15, figs. 

 4, 5; ModMes, 1826, No. 41.— Williamson, Rec. Foram. Great Britain, 1858, 

 p. 68, pi. 6, figs. 141, 142. — Parker and Jones, Philos. Trans., vol. 155, 1865, 

 p. 377, pi. 15, figs. 1-4; pi. 17, fig. 64a, h, c. — Dawson, Ann. Mag. Nat. Hist., 

 vol. 5, 1870, p. 178; vol. 1, ser. 3, 1871, p. 198; vol. 7, ser. 4, 1871, list, p. 88.— 

 Balkwill and Wright, Proc. Roy. Irish Acad., ser. 2, vol. 3, 1882, p. 447. — 

 H. B. Brady, Rep. Voy. Challenger, Zoology, vol. 9, 1884, p. 428, pi. 54, figs. 

 1-3. — Balkwill and Wright, Trans. Roy. Irish Acad., vol. 28, 1885, p. 335. — 

 H. B. Brady, Journ. Roy. Micr. Soc, 1887, p. 900.— H. B. Brady, Parker, 



