46 BULLETIN 161, UNITED STATES NATIONAL MUSEUM 



In its indented periphery C. subtumida tends toward C. angulosa, but 

 the angularity of the chambers is much less, the test is more bulging 

 in the middle, and the aperture is in a different position. 



Re-examination of the holotype and seven paratypes of C. rarilocula 

 Cushman has led me to regard them as immature specimens of C. 

 subtumida. The differences between these forms seem to be so 

 slight, and mostly a matter of degree, that I find it impossible to 

 maintain the two as distinct species. 



Genus ISLANDIELLA N0rvang, 1958 



This genus was erected to permit the separation of two kinds of 

 cassidulinids. Those in which the aperture is a tripartite opening 

 with two platelike lips attached to the inward-bent wall, partly 

 obstructing the apertural opening, remain in Cassidulina. Those in 

 which the aperture consists of a large basal rounded triangular 

 opening with an internal tooth and a free, projecting tongue partly 

 closing the opening are placed in Islandiella. A corresponding sepa- 

 ration of wall type — granular in Cassidulina and radiate fibrous in 

 Islandiella — is said to fall along the line of the separation based on 

 the nature of the aperture (N0rvang, 1958, p. 25). 



ISLANDIELLA sp. 



Plate 15, Figure 3 



Rare specimens were found in only a few of the samples. 



The species is shiny, white, and smoothly globular except for the 

 slightly protruding apertural end. Chambers and sutures are very 

 indistinct, but it appears that the test surface is composed of few 

 chambers. The aperture is relatively large, curved, crescent shaped, 

 with the edge of its outer curve bent smoothly inward and the edge of 

 its inner curve marked by a raised bladelike tooth. Greater diameter 

 0.45-0.55 mm., lesser diameter 0.35-0.45 mm. 



Genus CASSIDULINOIDES Cushman, 1927 



CASSIDULINOIDES TENUIS Phleger and Parker 



Plate 17, Figure 9 



Cassidulinoides tenuis Phleger and Parker, 1951, Geol. Soc. Amer. Mem. 46, 

 pt. 2, p. 27, pi. 14, figs. 14-17. — Parker, 1954, Bull. Mus. Comp. Zool., 

 vol. Ill, no. 10, p. 537, pi. 11, fig. 14. — Parker, 1958, Rep. Swedish Deep- 

 Sea Exped., vol. 8, Sediment Cores, no. 4, p. 272, pi. 4, figs. 18, 19. 



This slender, arcuate species was described from the Gulf of Mexico 

 and also reported from the Mediterranean. Rare specimens are 

 present in two samples near the Paumotu Islands. 



