1905 - 6 .] Collembola from the South Orkney Islands. 
481 
family it is apparently borne on the fifth. Willem (1900 ) has 
shown, however, that in reality it always belongs to the fourth. 
Thus we see that in the group of I. Brucei an ancient character 
has been retained, and the shore-haunting habit of all the species 
belonging to it is another mark of high antiquity. It seems 
probable, therefore, that I. Brucei is older than the typically 
Antarctic species ; and that, for the land connections over which 
its ancestors travelled, we must go back to early Secondary 
times. 
) It is startling to conclude that these frail insects of the far 
north and the remote south, now separated by thousands of miles 
of land and sea and ice, have passed through so great a length of 
geological time with such slight structural deviation from their 
common progenitors. 
REFERENCES. 
1905. W. S. Bruce, “Bathymetrical Survey of the South 
Atlantic Ocean and Weddell Sea,” Scot. Geog. Mag ., August 1905. 
1899. G. H. Carpenter and W. Evans, “The Collembola and 
Thysanura of the Edinburgh District,” Proc. R. Phys. Soc. Edin ., 
vol. xiv., 1899, pp. 221-266, pis. v.-viii. 
1902. G. H. Carpenter, “ Insecta Aptera,” in Report on the Col- 
lections of Natural History made in the Antarctic Regions during 
the Voyage of the “ Southern Cross,” pp. 221-3, pi. xlvii., London 
(British Museum), 1902. 
1903. G. Enderlein, “Die Insekten und Arachnoideen der 
Kerguelen,” in Wissenschaftliche Ergebnisse der deutschen tiefsee 
Expedition auf dem Dampfer “ Valdivia ,” 1898-9, vol. iii. pp. 
199-248, taf. xxi.-xxxvii., Jena, 1903. 
1899. J. W. Folsom, “The Anatomy and Physiology of the 
Mouth-parts of the Collembolan, Orchesella cincta, Linn.,” Bull. 
Mus. Comp. Zool. Harvard, vol. xxxv., 1899, No. 2. 
1905. F. W. Hutton, “Ancient Antarctica,” Nature, vol. lxxii., 
1905, pp. 244-5. 
1891. H. von Jhering, “On the Ancient Relations between 
New Zealand and South America,” Trans. Proc. N. Zeal. Inst., 
vol. xxiv., 1891, pp. 431-445. 
1904. A. Ortmann, Reports on the Princeton University Expedi- 
tions to Patagonia, 1896-1899, vol. iv., “ Palaeontology,” Part 2, 
“ Tertiary Invertebrates. ” pp. 45-332, pis. xi.-xxxix., Princeton, 
1904. 
PROC. ROY. SOC. EDIN. — VOL. XXVI. 
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