TROPICAL PACIFIC FORAMINIFERA OF "ALBATROSS" 41 



Cassidulina laevigata d'Orbignt var. carinata Cushman, 1922, U.S. Nat. Mus. 



Bull. 104, pt. 3, p. 124, pi. 25, figs. 6, 7. 

 Cassidulina neocarinata Thalmann, 1950, Contr. Cushman Found. Foram. 



Res., vol. 1, p. 44. — Parker, 1954, Bull. Mus. Comp. Zool., vol. Ill, no. 10, 



p. 536, pi. 11, fig. 3. 

 Cassidulina laevigata cTOrbigny.- — N0rvang, 1958, Vidensk. Medd. Dansk 



naturh. Foren., vol. 120, p. 38, pi. 9, figs. 27-31. 



Cassidulina carinata appears to be a cosmopolitan species but is 

 represented by only rare individuals in the present collections. It is 

 about equally biconvex with an angled and, in some specimens, keeled 

 periphery. Four pans of chambers compose the final whorl and the 

 aperture is an elongate narrow slit parallel to the suture that separates 

 the final two chambers. The outline of the test is slightly lobulated. 



After examination of the types of "Cassidulina laevigata var. 

 carinata Cushman," described from off Florida, and comparison of 

 them with the original figure of Cassidulina carinata Silvestri from 

 the Pliocene of Italy, as well as with specimens illustrated under that 

 name (see synonymy above), I conclude that the two forms should 

 not be separated specifically. As pointed out by Phleger, Parker, 

 and Peirson (1953, p. 44), in the Florida form the aperture is longer 

 than in the Italian one. Moreover, the Italian form is reported 

 (loc. cit.) to have a broader apertural face, to be less compressed, and 

 to be more coarsely perforate. Inasmuch as these and other features 

 appear not to hold true but to be transitional, I interpret these two 

 forms as one and use Silvestri's earlier name. 



As to the relationship between this form and d'Orbigny's Cassidulina 

 laevigata, that question must remain open because the source of the 

 species, "ballast sand," is indeterminable. Cassidulina laevigata is 

 shown as similar to the present species in its angular periphery but 

 has no keel. It differs from the present species in its short bulimine 

 apertural opening set at an angle to the suture line. As C. laevigata 

 is type species of the genus, its loss into limbo might be interpreted 

 by some as equivalent to loss of the genus Cassidulina; however, the 

 morphology of the test is delineated clearly by the original figure 

 and the model and has long been universally understood. In the 

 interest of stability of nomenclature, the generic name should not be 

 abandoned because the specific character of its type species is 

 indeterminable. 



CASSIDULINA COSTATULA Cushman 



Plate 17, Figure 8 



Cassidulina costatula Cushman, 1933, Contr. Cushman Lab. Foram. Res., vol. 9, 

 pt. 4, p. 94, pi. 10, fig. 7.— Cushman, Todd, and Post, 1954, U.S. Geol. 

 Surv. Prof. Paper 260-H, p. 365, pi. 90, fig. 24. 



