146 



UNITED STATES NATIONAL MUSEtJM BtTLLETIN 216 



are drawn ("tlberlappimgen") , with correspondent 

 costae ("dariiber ungelagerten Kalkrippen"). His fig- 

 ure 4b shows the same character. 



Some new mternal characters were recognized in the 

 present study. Specimens were examined in trans- 

 mitted light at X216 magnification, and in order to 

 obtain more complete evidence of the septal surfaces, 

 some specimens were progressively acid-treated imtil 

 final dissolution of the septa allowed an examination of 

 the internal surface of the wall. In longitudinal section 

 the chambers are semilimar or strongly arched, depend- 

 ing on their position as related to the proloculum and 

 to the lateral extension of the test. The septa are very 

 thick; they have often the same thickness as the 

 chamber cavities themselves in the young stage; in the 

 adult stage they gradually become thinner. The 

 septal smface is flat, not undulated. The marginal 

 undulation is simulated by the septa encoimtering an 

 internally tuberculate wall (fig. 14). The large tuber- 

 cules are present also ia the central area and are aligned 

 with the external sculpture. 



In conclusion, the present investigation confirms the 

 validity of the genus Bolivinoides Cushman. It should 

 not be placed near Bolivina, because of its very dis- 

 tinctive characters, the structure of the wall, sculpture, 

 test shape and proportion, and it comprises an homo- 

 geneous group of species with a distinctive strati- 

 graphical development. 



Hiltermann and Koch (1950, p. 626) consider 

 Bolivina watersi Cushman as an extreme form of 

 Bolivinoides. However, B. watersi, which has a neck 

 and terminal aperture, has recently been made the 

 basis for a distinct genus, Trachelinella Montanaro 

 GaUitelli. 



Genus Bolivinita Cushman, 1927 



Plate 33, Figtjhbs 17-20 



Bolivinita Cushman, Contr. Cushman Lab. Foram. Res., vol. 2, 

 p. 90, 1927. 



Type species: TextHaria quadrilatera Schwager, 1866, 

 lower Tertiary, from Kar Nikobar, "British India." 



Diagnosis: Test biserial, elongate, gradually en- 

 larging in size, rectangular in transverse section and more 

 or less compressed, with four strongly developed and 

 sometimes lamellar axial costae at the angles; broader 

 sides flat or moderately concave. Chambers elongate, 

 irregularly pyriform or reniform, more inflated laterally. 

 Earliest chamber with one basal spine in the micro- 

 spheric and two or more spines in the megalospheric 

 forms. Sutures straight and thin at the narrow sides, 

 occasionally strongly limbate and oblique in the broader 

 faces, where they form an angle of about 90 degrees, 

 strongly arched and fused one to another at the lateral 

 end of the broader faces, forming the lamellar longi- 

 tudinal costae. Wall thin, calcareous, completely 

 covered with minute pores and sporadic larger ones; 

 frequently spinose and sometimes vertically costate in 

 the early stage. Apertiure basal, subcircular, elliptical, 

 with major axis perpendicular to the suture and pro- 



vided with a fairly well developed lip which may be 

 present also in the sutural area. Apertural tooth 

 moderately or not projecting, somewhat arched at the 

 upper surface, enlarged internally in an oblique spout 

 (toothplate) , which is developed along either one or 

 another of the sides of the chamber, and may be spatu- 

 late at the free lower end. 



Discussioisr: A plesiotype incorrectly figured by 

 Cushman is here refigured. The other specimens are 

 similar to those studied and illustrated by Hofker 

 (1951b, p. 104) for comparison in following his mor- 

 phological and structural studies. They probably 

 represent a different species but the generic characters 

 are constant. The results obtained by Hofker con- 

 cerning the toothplate were substantiated, but other 

 new structural details were also observed. The plate 

 is variable in size, concavity, position in the apertural 

 cavity, and development of the final spatula. One 

 correction is necessary. Text-fig. 61d of Hofker 

 fl951b, p. 105) represents the apertm-e limited in the 

 ventrodorsal direction by a strongly limbate, arched 

 septum. Not one of the approximately one hundred 

 specimens of Bolivinita quadrilatera investigated from 

 a single sample present such a character. In fact, the 

 anterodorsal portion of the septum between the pen- 

 ultimate and the final chamber is not visible externally 

 because it is situated internally to the aperture; the 

 arch of the aperture ends in contact with a fold of the 

 upper terminal surface of the penultimate chamber. 



The conclusion of Hofker (1951b, p. 102) as to the 

 systematic invalidation of this genus and its placement 

 within the genus Bolivina seems hardly acceptable, at 

 least imtil more is known about the importance of 

 the toothplate, and until a correlation between the 

 variability of this structure and that of other morpho- 

 logical characters is established. Investigations at 

 high magnification, by thin sections and dissections, 

 even in very minute specimens now show that internal 

 processes are more common than was previously sus- 

 pected, and we need much more evidence before estab- 

 lishing a new systematics on this basis alone. Further- 

 more, a systematics based only on toothplates and pores 

 cannot consider the vast number of fossil Foraminifera 

 where these characters are lacking or concealed by the 

 process of fossilization, or obscure due to their minute 

 size. Without further evidence, such a revision would 

 result in confusion rather than order. 



The toothplate represents only a single character, 

 just as does the position and form of the apertiire, the 

 chamber arrangement, or the chamber shape. In a 

 group of specimens from a single sample, the position, 

 development, and shape of the toothplate may be 

 quite variable. 



Hofker (1951b, p. 107) stated "There is no reason 

 why we should create a new genus only distinguished 

 from the central genus by an ornamentation of the 

 wall." Nevertheless, the presence of four vertical 

 carinae is more than a question of ornamentation; it is 

 the consequence of a completely different chamber 

 shape. The chambers in Bolivina are generally reniform 



