NATURE 



[September 8, 192 1 \ 



Species in Foraminifera. 



ATTENTION should have been directed sooner 

 than now to an interesting paper by Messrs. 

 E. Heron-Allen and E. Earland on the species of 

 Verneuilina polystropha and some other Foraminifera 

 (Proc. Roy. Irish Academy, vol. 35, Section B, 

 No. 8, pp. 153-77, 3 pis.). It is in part a contribu- 

 tion to the study of variation in the Foraminifera, 

 and in part an account of certain experiments^^ vi^hich, 

 to say the least, are verv suggestive to those interested 

 in the problem of species. Variation in Foraminifera 

 may affect the size of the primordial chamber, the 

 plan or arrangement of the chambers, and the external 

 form. The authors also discuss the occurrence of 

 gigantism and nanism, the predominance of the 

 chitinous membrane . over the calcareous shell, and 

 the changes involved in a free or adherent mode of 

 life within the same species. The facts seem to the 

 authors to prove the futility of all classifications of 

 Foraminifera based on the external shell, but the 

 difficulty is to find any other basis. 



The normal Verneuilina polystropha is a remark- 

 ably constant form, singularly free from the variations 

 and monstrosities which occur in normal circum- 

 stances among other Foraminifera. It shows 

 dimorphism, represented by a long form which is 

 megalospheric and bv a short form which is always 

 microspheric. The megalospheric primordial chamber 

 is sometimes divided into two chambers by an 

 internal chitinous septum. Dwarf or pigmy forms 

 also occur which cannot be confused with young 



specimens. . . t7 i. ? 



Experiments go to show that there is in V. poly- 

 stropha a -marked tendencv to select and incorporate 

 heavy minerals among the normal siliceous sand 

 grains A number of the specimens utilised gem- 

 splinters "of a size and shape utterly disproportionate 

 to the size of the tests, thus producing a variety 

 which presents a striking contrast to the norrnal 

 tvpe " The observation would have had greater value 

 if the number of specimens that "selected" large and 

 heavy gem-splinters had been given, so that it might 

 be compared with the number that had simply in- 

 corporated gem-sand and with the number of those 

 that kept to ordinarv ^and. Fifty per cent, of ordinary 

 sand was supplied along with the gem-sand. Another 

 observation records the occurrence of monsters in 

 considerable proportion in a tank with sea-water ren- 

 dered hvpertonic bv doubling the normal hme-content 

 The paper points to the idea that in a natural 

 svstem of Foraminifera the processes of construction 

 and habits of growth and reproduction must count as 

 of more value than the material employed in the con- 

 struction of the test.' We hope_ that the authors wil 

 make their proof of the "selection " of shell-material 

 more convincing. It is a very important point. 



I 



Biological Statistics. 



N the first article in the current issue of Biometrika 

 - (vol. 13, parts 2 and 3, July, 192 1, Cambridge 

 University Press, 255.) Prof. Karl Pearson and Miss 

 \ G Davin give us a study of the sesamoids of the 

 "knee-joint in man. The best-known works on the 

 subject are those of Gruber and Pfitzner, but, as a 

 whole, the records of these bones are scanty and un- 

 satisfactorv, so that an up-to-date attempt to deal 

 with the subject, using the evidence obtained from 

 skiagrams, is welcome. It has been stated fairly 

 freelv in the past that sesamoids are manufactured 

 from' cartilage by intensive stress, but the authors 

 point out, and adduce evidence in support of the 



NO. 2706, VOL. 108] 



view, that it is more probable that they are vestiges 

 of some structure of earlier form. The available 

 measurements show that there are orthosesamoidal 

 (true bone sesamoid) lateral fabellae in about 7 per 

 cent, of the knee-joints of man, and few, and possibly 

 no, cases of orthosesamoidal mesial fabellae. Part of 

 the paper is devoted to an interesting historical note 

 on the subject, including a discussion of the "sesame," 

 from which the name "sesamoid" is derived; it is 

 written in a way that is a pleasant reminder of the 

 spirited manner of some historical studies published 

 by one of the authors a good many years ago. 



Miss Tildesley contributes a paper on the Burmese 

 skull, which is a valuable continuation of the large 

 amount of useful measurement and investigation that 

 has already been done at University College, London. 

 The present work is based on 142 skulls procured by 

 the late Col. P. H. Caster from the neighbourhood 

 of Moulmein, and the material is divided according to 

 sex and also into three groups according to race— or 

 supposed race. Miss Tildesley gives a large number 

 of measurements for each skull, and in comparing her 

 results with such measurements as she could find of 

 Chinese, Hindu, etc., skulls, she gives a coefficient, 

 suggested by Pearson, which may be helpful in 

 measuring race-likeness. Whatever view may be 

 taken by craniologists with regard to this index, they 

 will at any rate be grateful for the material col- 

 lected and published, and approve the way in which 

 Miss Tildesley displays her facts and puts all her 

 cards on the table, so that others have the oppor- 

 tunity of drawing their own conclusions. We may 

 particularly commend as an aid to comparison th(_ 

 loose contours on thin paper. The article contains 

 a useful table for calculating the occipital index, and 

 gives evidence of the agreement of measurements 

 obtained directly from the skulls with those obtained 

 from contours. 



"Student" continues his studies of probable error- 

 commenced in earlier issues, and gives, on the basi- 

 of extensive sampling, an experimental determinatio! 

 of the probable error of Dr. Spearman's correlation 

 coefficients obtained by replacing actual measurements 

 by ranks. This experimental method seems to us the 

 sound way of getting down to the real distribution of 

 deviations; it affords the right kind of check on any 

 theoretical statistical investigation- The issue also 

 contains a further mathematical article by Prot 

 Tchouproff, of Petrograd, on "The Mathematical 

 Expectation of the Moments of Frequency E>istribu- 

 tions " and one confesses to a feeling of wonder that 

 work of this kind can be produced from Petrograd 

 at the moment. There are also three short notes by 

 Prof. Pearson and a review by' Miss Elderton ot an 

 American study of women delinquents.^ 



It will be seen that the issue contains papers that 

 should interest different classes of scientific readers, 

 and it mav be added that the journal, which is pro- 

 duced bv the Cambridge University Press, is well up 

 to the standard which we have grown to expect of 

 that press. 



University and Educational Intelligence. 



CvMBRiDGE.— Applications for the George Henry 

 Lewes studentship in physiology, shortly to be vacant, 

 should be sent with a brief statement of the candi- 

 date's qualifications, the subject of his Proposed ^e- 

 search, and the name of a referee, to Prof. Lan^^y. 

 the Phvsiologv School, by October i. The student- 

 ship is 'of theannual value of about 245[-. tenable for 

 one to three vears at the discretion of the trustees. 



