NO. 5 FORAMINIFERAL GENERA — LOEBLICH AND TAPPAN 1/ 



Diagnosis. — Test free, discoidal, early portion milioline in plan, later 

 planispiral and slightly involute, with three to six chambers in the final 

 whorl, the later chambers being relatively shorter, so that the number 

 per whorl gradually increases; wall thickened, calcareous, imperforate; 

 aperture consists of numerous irregular pores in a trematophore, the 

 marginal row of pores being left exposed in the earlier chambers and 

 remaining as sutural pores connecting with the interior. 



Types. — The specimen of figure i (B.M.N.H. No. ZF 3629) is here 

 designated as lectotype. It is from Challenger station 187A, at a depth 

 of 8 fathoms, ofif Booby Island, and is the specimen figured originally 

 by Brady. The sectioned specimens (figs. 2, 3) are in the collection 

 of the U.S.N.M. (No. P 2i97a,b) and are from Torres Strait. 

 Brady's other syntypes are here considered paratypes (B.M.N.H. 

 No. ZF 1565) and are from the same locality as the lectotype. 



Discussion. — In the description of the genus Polysegmentina, Cush- 

 man ( 1946, p. i ) stated that "A study of the structure and develop- 

 ment of this form [Hauerina circinata Brady] shows that it is not a 

 Hauerina, as the early stages are not quinqueloculine but apparently 

 planispiral and related to Cornnspira." He described Polysegmentina 

 as having "the early stages similar to Cornuspira with proloculum 

 and planispirally coiled second chamber several coils in length." 

 This description was apparently based on a misinterpretation of a 

 figure given by Rhumbler (1906, pi. 3, fig. 40), an exterior view 

 (copied by Cushman, 1946, pi. i, fig. 4) which seemed to show a 

 planispiral early development. Examination of Brady's types in the 

 British Museum shows that this apparent planispiral coiling is only 

 the faint surface reflection of the spiral suture, largely obliterated by 

 the thin shell layers of the later nearly involute coils, and that only the 

 chambers of the last one and one-half or two whorls can be determined 

 surficially. We have had thin sections prepared and these show that 

 the early portion is milioline and definitely not planispiral, and that 

 there is no undivided second chamber of several coils in length. 



Brady had even stated (1884, p. 190) that he placed in Hauerina 

 only "the planospiral porcellaneous Foraminifera which are Milioline 

 only in the very early stages of growth," and although he had not 

 sectioned the species as proof, his statements, as so often found, were 

 closer to being accurate than those of later workers. The bases on 

 which Cushman separated this species from Hauerina are completely 

 invalid and do not warrant its separation as a separate genus. 



However, the genus Polysegmentina may be separated on a different 

 basis, and we are here emending the diagnosis, separating this genus 

 from Hauerina because of the peculiar retral processes along the 



