[62 UPPER CRETACEOUS-LOWER TERTIARY FORAMINIFERA 



quadriglobular, inflated ; equatorial periphery quadrate, distinctly lobate ; axial 

 periphery rounded ; chambers on the dorsal side appear to be 16-19 m number, 

 arranged in 4 dextrally coiled whorls ; the initial chambers are extremely small, 

 indistinct, slightly inflated, globigerine and increase slowly and regularly in size to 

 the beginning of the last whorl, where the chambers increase rapidly in size ; the last 

 whorl thus constitutes most of the test, while the early chambers constitute a minute, 

 high, trochoid spire ; the last whorl is composed of 4, relatively large, almost globular 

 chambers ; on the ventral side the chambers are 4, relatively large, globular and 

 inflated ; sutures on the dorsal side curved, depressed in the early part, straight 

 and strongly incised later ; on the ventral side the sutures are straight, radial, 

 strongly incised, set almost at right angles to each other in a cruciform pattern which 

 emphasizes the quadrate shape of the test ; umbilicus exceedingly small, almost 

 closed and indistinct ; aperture interiomarginal, umbilical ; wall calcareous, finely 

 perforate ; surface rough, hispid, covered by minute, delicate spines, and very small 

 scattered papillae. 



Dimensions of described specimen. 



Maximum diameter = 0-175 mm. 

 Minimum diameter = 0-130 mm. 



Thickness = 0-160 mm. 



Main variation. 



1. The test is minute to small (maximum diameter ranges from 0-12 to 0-28 mm.) 



2. The dorsal spire may be moderately raised to high. 



3. The number of chambers in the last whorl is 3-4, 3! is most common. 



4. Coiling is fairly random but tends to be dextral ; (of 175 specimens studied, 98 



coiled dextrally). 



5. The small, shallow, open umbilicus may be partially closed by the slightly 



overlapping last chamber. 



6. The fine surface spines are always present and may be prominent and numer- 



ous or very faint and scattered. 



Remarks. Globigerina daubjergensis Bronnimann is distinguished by its extremely 

 small, trochospirally coiled test, its minute, pointed spire on the dorsal side, its 

 rough, finely spinose wall surface, its small shallow umbilicus and small umbilical 

 aperture, its strongly depressed sutures on both sides, and distinctly lobate periphery. 



Because of its extremely small size, this excellent Danian guide fossil was probably 

 overlooked in the past or lumped together with superficially similar Globigerina 

 species. Troelsen (1957) recorded this species from the type Danian and from 

 various Danian outcrops in Scandinavia, where he noticed, for the first time, the 

 occurrence of small, accessory, sutural apertures on the dorsal side of some of the 

 specimens. These accessory apertures caused disagreement whether the species 

 should be referred to Globigerina or to Globigerinoides, and the problem was further 

 complicated by the fact that specimens with and specimens without accessory 

 apertures were found together. Troelson added " Small accessory apertures 

 commonly occur along the sutures of the final chamber, but the writer has, neverthe- 



