108 



BULLETIN 104, UNITED STATES NATIONAL MUSEUM. 



CRISTELLARIA ROTULATA (Lamarck) ? 



Plate 22, fig. 2, pi. 28, figs. 1, 2. 



Description. — Test comparatively large, close-coiled, strongly 

 uinbonate, carinate or the periphei-y angled, the last-formed coil 

 composed of few, not usually more than 7 or 8, chambers; sutures 

 distinct, straight, not extending to the center of the test, but to the 

 umbo so that each chamber overlaps the preceding; surface smooth 

 throughout; aperture at the peripheral angle of the test, large, 

 radiate. 



Diameter up to 2.50 mm. 



Distribution. — I have limited the name Gristellaria rotulata to 

 this simple type composed of a few chambers, with very large um- 

 bonat'e center, and the sutures of a peculiar type, shown in plate 28, 

 figure 2. Such specimens are found especially in the Gulf of Mex- 

 ico, Caribbean, and in the warmer portions of the western Atlantic. 

 They also occur in the Tertiary of the Gulf Coastal Plain of the 

 United States. Such specimens are also found in the Indo-Pacific 

 and are probably related to these. Also in the Gulf of Mexico there 

 are found specimens more like those figured by Brady as GHstel- 

 laria rotulata.^'^ This has many more chambers, the sutures are 

 curved, and their arrangement where they impinge against the cen- 

 tral umbo is different. Such forms may possibly be varieties of 

 Cristellaria iota Cushman which lack the peripheral keel. 



Gristellaria rotulata — material examined. 



CRISTELLARIA VORTEX Fichtel and Moll. 



There are a few records for this species from both sides of the 

 Atlantic. Brady records it from off Bermuda at 435 fathoms (796 

 meters) , Goes records it as scarce in the Caribbean Sea, 130 fathoms 

 (238 meters), and Flint from the Caribbean and the eastern coast 

 of the United States in 130 and 276 fathoms (238 and 505 meters). 



» Rep, Voy. Challenger, Zoology, vol. 9, 1884, pL 69, flj. 13. 



