IN THE ESNA-IDFU REGION, NILE VALLEY, EGYPT 69 



ventral keel of nepionic stage (when present) continues as ventral inter-cameral 

 suture, ventral marginal keel of last whorl and sometimes as umbilical flange. In 

 single-keeled forms keel occasionally bifurcating on periphery to form dorsal as well 

 as ventral inter-cameral suture, as in members of Globotruncana stuarti group. 



Discussion. Cushman (19276) described Globotruncana as a new genus, with 

 Pulvinulina area Cushman 1926 as the type species. However, several species of 

 this genus had been previously assigned to the genus Rosalina d'Orbigny 1826 

 (e.g. R. marginata Reuss 1845, R. canaliculata Reuss 1854 an d R- stuarti de Lapparent 

 1918). Thalmann (1933) considered Rosalina d'Orbigny to be a junior synonym of 

 Discorbis Lamarck 1804, and thus substantiated the validity of the genus Globo- 

 truncana. However, Brotzen (1948) stated that the type species of Discorbis 

 Lamarck has not been determined for certain, and thus retained Rosalina d'Orbigny 

 1826, and included in its synonymy : Discorbina Parker & Jones 1862, and Discorbis 

 Lamarck of authors (part). Nevertheless, the apertural characters, the large 

 umbilicus, the umbilical cover-plate, the keels and peripheral band, the shape of the 

 chambers, etc., clearly distinguish Globotruncana from the above genera. 



The brief description of the apertural characters of the genus given by Cushman 

 (19276) led to further complication. He merely stated that the aperture is on the 

 ventral side, and later (1928) added "... aperture on the ventral side, often in 

 well-preserved specimens with a thin plate-like structure over the umbilical area ..." 

 However, Marie (1941) noticed that in morphologically similar forms, the apertures 

 of the previous chambers remain open into the umbilicus. Thus he suggested 

 including these forms in a separate genus which he named Rosalinella, with R. linnei 

 (d'Orbigny) as type species. He included within his new genus : Rosalina d'Orbigny 

 sensu de Lapparent 1918, Globotruncana Cushman 1927, Globorotalia Cushman 1927 

 (part), as well as Rosalna d'Orbigny (part), Discorbina Parker & Jones (part), 

 Globigerina d'Orbigny (part), Rotalia Lamarck (part) and Truncatulina d'Orbigny 

 (part) of authors. Marie divided his genus Rosalinella on the basis of the peripheral 

 character and general form of test into four subgenera which he did not name, but 

 listed with examples as follows : 



I. Test with truncated periphery, bordered by two marginal keels. 



1. Subgenus typified by Rosalinella linnei (d'Orbigny). 



II. Test with acute periphery (single keeled) : 



(A) Contour regular 



[a] with large umbilicus. 



2. Subgenus typified by Rosalinella stuarti (de Lapparent). 



[b] with narrow umbilicus. 



3. Subgenus typified by Rosalinella velascoensis (Cushman). 



(B) Contour lobate 



4. Subgenus typified by Rosalinella appenninica (Renz). 



Thus, he included within his new genus, species typical of Globotruncana Cushman 

 1927, of Globorotalia Cushman 1927, and of Rotalipora Brotzen 1942. Nevertheless, 

 his description conforms well with that of Globotruncana as given by Cushman 



