266 



SCIENCE 



[N. S. Vol. XLIX, No. 1263 



collected seems to show difierences from its 

 Ehynclionellid relatives which have induced 

 the author to propose for it a new genus 

 Compsothyris, though no new species were ob- 

 tained. The paper is illustrated by an excel- 

 lent plate and has a bibliography of the more 

 important literature. 



Australasian Aiitarctic Expedition, 1911-14, 

 Scientific Reports, Series _ 0. — Zoology and 

 Botany, Vol. BI., pt. 1, 4to. " Calcareous 

 Sponges," by Professor Arthur Dendy, pp. 

 1-17, 1 pi.; Vol. III., pt. 2. " Pterobranohia," 

 by W. G. Ridewood; 26 pp., 1. pL; Vol. V., pt. 

 5, " Euphausiacea and Mysidacea," by W. M. 

 Tattersall; 16 pp. and 1 pL; Vol. IV., pt. 3. 

 " Bi-achiopoda," by J. Allen Thomson, pp. 76, 

 and 4 pi. ; Vol. V., pt. 6, " Cumacea and Phyl- 

 locarida," by W. T. Caiman, pp. 12 and 1 pi. 

 Sydney, W. S. W. Government Printing Office, 

 1918. 



The continued publication of these purely 

 scientific papers before the cessation of active 

 military operations and in despite of financial 

 stresses, reflects credit upon the government 

 of Australia. The citizens of that common- 

 wealth have naturally taken great pride in the 

 success of their expedition and its valuable 

 results for science, and these handsomely pub- 

 lished memoirs are an expression in part of 

 that pride. 



The number of calcareous sponges from the 

 Antarctic is small, but to them are added a 

 number collected off Tasmania and at Mac- 

 quarie Island. The collection includes two 

 new species of Leucetta and one of Leucandra. 



Dr. Eidewood's memoir contains no new 

 species but forms a useful review of the 

 austral species of Cephalodiscus with a bib- 

 liography of the rather scanty literature. 



Dr. Tattersall treats of four species of Eu- 

 phausians and two of Myacids, one of the latter 

 from the Auckland Islands being new is de- 

 scribed as Tenagomysis tenuipes. Dr. Cai- 

 man describes a new species of Diastylis and 

 reviews forms of Nehalia and Cyclaspis, which 

 fill a wide gap in our knowledge of their geo- 

 graphical distribution. Dr. Thomson's memoir 

 on the Brachiopoda is of particular impor- 

 tance, comprising a review of the group in 



the southern hemisphere, the description of 

 new forms, and an interesting discussion of 

 the relations of the existing forms to their 

 fossil precursors and their distribution in con- 

 nection with theories of previous land con- 

 nections between the different continents in 

 earlier geological time. His conclusion is 

 that the present distribution lends probability 

 to the hypotheses of von Ihering and others 

 which assume such linking up of the various 

 bodies of land in the later Mesozoic epoch. 

 The paper has an excellent bibliography, but 

 it is to be regretted that the phototyped figures 

 in many eases are insufficiently clear to show 

 the details mentioned in the text. 



"W. H. Dall 



SPECIAL ARTICLES 



ROTARY VERTIGO IN THE TAIL-SPIN 



In the tail-spin, an evolution that is standard 

 among military and exhibition aviators and 

 into which any flier is apt to fall accidentally, 

 a marked rotary and post-rotary vertigo may 

 be induced. As the maintenance of the correct 

 flying attitude of the airplane is largely de- 

 pendent upon the pilot, this disturbance in his 

 idea of attitude may lead to serious conse- 

 quences and its significance and characteristics 

 merit definition. A true appreciation of the 

 phenomenon should increase the confidence of 

 the young pilot just becoming acquainted with 

 the evolution and decrease the risk attached 

 to this feature of aviation training. 



Purkinje in 1820 (quoted from McKend- 

 riek^) directed attention to the well-known 

 vertigo of rotation. In brief, when the move- 

 ment of the hody is arrested after undergoing 

 rotation — 



(1) an after-sensation of rotation in the 

 same direction is experienced. In coming out 

 of the spin and levelling off, the pilot experi- 

 ences a sensation of rotation after that has 

 actually ceased. He therefore, tends to over- 

 control, with the consequent danger of falling 

 into another sipin in the opposite direction. 



(2) The axis of this imaginary after-sensa- 

 tion of rotation is that axis of the head ahout 



iSclhafer's "Text-Book of Physiology," 1900, 

 II., p. 1196. 



