STUDIES m FORAMmrFERA 



135 



of the aperture; (4) presence, development and shape 

 of the "toothplate" or columellar process. 



Coiling in the early stage is present more or less 

 frequently in: Heterohelix americana (fide Ehrenberg), 

 H. navarroensis, Guembelina globulosa, G. glohocarinata, 

 G. planata, G. striata, G. glabrans, and G. psendotessera 

 (=(?. pulchra Brotzen). Both Heterohelix navarroensis 

 and Guembelina spp. also have a variable percentage of 

 specimens with the early stage uncoiled. Considering 

 that no other differences previously separated Guem- 

 belina from Heterohelix (Galloway (1933, p. 343) states 

 that "Guembelina differs from Heterohelix only in the 

 absence of the spiral, early stage"), there is no further 

 reason to uphold their generic separation: consequently 

 Guembelina Egger is here considered a junior synonym 

 of Heterohelix Ehrenberg. 



An occasional or constantly coiled early stage in 

 Tubitextularia, Pseudotextularia, Gublerina, Pseudo- 

 guembelina, Piano globulina, and the new genus Racemi- 

 guembelina is here demonstrated. This character is 

 documented for each genus in the illustrations. 



Loeblich (1951) demonstrated that Eouvigerina has 

 no coiling in the early stage. This observation is 

 confirmed by the present investigation and in addition 

 three other genera, described previously as "coiled," 

 are demonstrated to be constantly and clearly biserial: 

 BolivineUa (according to Cushman (1929, p. 28) "in 

 the microspheric form the young [is] apparently plani- 

 spiral"), Bolivinoides and Plectojrondicularia. Among 

 the "Heterohelicidae," therefore, coiling is present only 

 in the genera related also by other characters to the 

 genus Heterohelix. 



The exact position and shape of the aperture is here 

 described for each genus. This important character 

 has been neglected or erroneously described in some 

 genera; in others neither the description nor the figures 

 give any indication as to the apertural characters. The 

 present investigation, involving some thousands of spe- 

 cimens demonstrates that (1) the genera closely related 

 to Heterohelix have a simple basal arched aperture as 

 previously described ; of this group, only the accelerated 

 genus Tubitextularia, with an adult uniserial stage, has 

 an obviously terminal aperture and this is always 

 simple, without a lip; (2) a basal aperture with lip is 

 present in Bolivinoides, Bolivinita (the drawings by 

 Hofker are discussed in the systematic description), and 

 Tappanina; (3) a simple, open terminal aperture is 

 present in the genera Zeauvigerina and Trachelinella; 

 (4) a terminal apertm-e, reduced to an elliptical opening 

 by internal tubercles or costae, is observed in Bolivini- 

 tella and Plectojrondicularia; and (5) a radiate cribrate 

 aperture is observed in Amphimorphina and a typically 

 cribrate aperture seems to be occasionally present in 

 Bolivinella. 



No internal columellar processes (the "toothplate" of 

 Hofker) were mentioned by Cushman (1927a, p. 64) 

 for this family but Hofker (1951b) recently described 

 the "toothplate" in Bolivinita and, less carefully, in 

 Bolivinoides. Stone (1946) illustrated the same charac- 

 ter for Siphogenerinoides. In the present investigation 



an internal process is also demonstrated for Eouvigerina 

 and Pseudouvigerina. Bolivinoides has no "plate" but 

 a continuous tube arising from the first chamber. 

 Bolivinita has a "plate" (spout) which is extremely 

 variable in shape, size, concavity, position in the aper- 

 tural cavity, and development in the final "spatula." 

 In Siphogenerinoides the internal "tube" is actually a 

 spoutlike discontinuous interapertural process, whose 

 single divisions alternate in opposite tangential posi- 

 tions to the aperture, with the concavity always turned 

 towards the wall. This character gives a peculiar ap- 

 pearance to the apertural outline, which was misin- 

 terpreted by Stone. Eouvigerina has a very thin colu- 

 mellar process, apparently tubular and continuous, 

 beginning with the youngest stage. Pseudouvigerina 

 has a discontinuous spoutlike process, which is very 

 clear in the final chamber. Such a great variabihty of 

 this inner skeleton seems to require further study in 

 order to establish its value in the systematics of Fora- 

 minifera. 



The internal characters of the wall in the genus 

 Bolivinoides were investigated by Hofker (1952), and 

 some corrections of his observations concerning the 

 morphology and structure of the septa are given here. 

 In addition, it is noted here that the internal surface of 

 the wall is iiTegularly tuberculate, a most distinctive 

 peculiarity of this genus, which is thus considered 

 entirely valid, and not synonymous with Bolivina as 

 aflBrmed by Hofker (1951b), Glaessner (1945), Sigal 

 (1952), and others. 



Morphological Types Recognized 



The present revision does not presume to give a 

 satisfactory reclassification of all the 23 genera included 

 by Cushman (1948) in the family Heterohelicidae. A 

 complete revision of all the type species and of a large 

 number of specimens is necessary; the same has to be 

 done for the related families and superfamilies of Fora- 

 minifera and the results compared. Moreover we do 

 not know at present which character or characters in 

 the Foraminifera have an actual genetic value, and in 

 this respect the research of Arnold, Grell, and others 

 on living Foraminifera is welcome. 



It is possible here only to give an emendation of the 

 family Heterohehcidae, and a short systematic discus- 

 sion of the other genera formerly included in that family, 

 with some new infomaation as to their structural details. 



Many specimens, in addition to those here illustrated, 

 were partially acid-treated in order to show series of 

 transitional forms and structural details. It was im- 

 possible to illustrate all these, hence references to these 

 additional slides in the collections of the U. S. National 

 Museum, are given in the systematic descriptions. 



The terminal apertiu-e is found in this family, as here 

 restricted, only as an expression of an accelerated de- 

 velopment from a typical "guembelinoid" genus, as in 

 Tubitextularia Sulc {=Rectoguembelina Cushman) where 

 the first heterohelicoid stage is clearly visible. Five 

 different morphological types are distinguishable: 



