54 



NATURE 



[March 20, 1919 



REPORTS OF THE AUSTRALIAN 



ANTARCTIC EXPEDITION. 



'TTHE scientific results of the Australian Antarctic 



-•• Expedition are being published with commend- 

 able promptitude. Of the five parts recently received 

 the most generally interesting is the report on the 

 Brachiopoda by Dr. J. Allan Thomson, Wellington, 

 N.Z. The Brachiopods recorded, though not many in 

 number, are relatively rich in species, a new genus, 

 Amphithyris (family Terebratellidae), and new species 

 of seven other genera being described. The author 

 gives a summary of the known distribution of Brachio- 

 pods in South Temperate and Antarctic seas, and dis- 

 cusses the bearing of the facts on the theories of 

 southern land connections, "which it is one of the 

 aims of Antarctic expeditions to prove or disprove." 

 He points out that the known larvae of Brachiopods, 

 with the exception of those of Lingula and Discina 

 (sensu lato), have no mouth during the free-svcimming 

 stage, and that they soon settle down. Consequently, 

 the deep oceans are barriers which Brachiopods, the 

 majority of which live on the submarine slopes of con- 

 tinents and adjacent islands, and their larvae cannot 

 cross, and therefore cases of discontinuous distribution 

 of these shallow-water forms have an important 

 significance. 



Dr. Thomson considers there is abundant evidence, 

 from the associated molluscan fauna, that the Pata- 

 gonian (Miocene) of South America and the Oamaru- 

 ian (older Tertiary) of New Zealand had a much 

 warmer climate than the present, and that the oc- 

 currence of the same Brachiopod genera and species 

 in the Oligocene-Miocene of the Antarctic strongly 

 suggests that at this period the Antarctic seas were 

 also warmer. Mr. Tate Regan, in his report on the 

 Terra Nova fishes, inclined to the view that the coasts 

 of Antarctica were washed by cold seas probably 

 throughout the Tertiary period, but in Dr. Thomson's 

 view the geological evidence all points the other way. 



From a consideration of the distribution of the 

 Brachiopods he arrives at the following conclusions : 

 Connections — not necessarily land-bridges, but chains 

 of islands or shallow submarine ridges — must have 

 existed between Australia and South Africa at some 

 date prior to the Tertiary, by which the primitive 

 genera of the Terebratellidae attained their present dis- 

 tribution in South ^rica, St. Paul's and Marion 

 Islands, Australia, and New Zealand. The specific 

 and generic distinctness of the recent New Zealand 

 and Australian forms precludes any land connections 

 between these areas in Pliocene or later times. The 

 two groups of Terebratellidae concerned would seem 

 to have originated on the coasts of Gondwana Land, 

 on the remnants of which they now survive ; the Ker- 

 guelen area apparently did not share in the connection 

 with Gondwana Land. Connections between Aus- 

 tralia, New Zealand, the Macquarie Islands, Ker- 

 guelen, Antarctica, and South America must have 

 occurred in the early Tertiary, but New Zealand was 

 not connected at the same time w^ith Australia and 

 Antarctica. The connections between New Zealand, 

 Antarctica, and South America may have existed from 

 an earlier period. It does not appear probable that 

 Australia was connected directly with Kerguelen and 

 Antarctica during the Cretaceous or early Tertiary. 

 The southern connections were broken, much as at 

 present, by Miocene times, and since that period there 

 have been no renewed connections between the 

 southern continents and island areas except, possibly, 

 between South America, Antarctica, and the adjacent 

 islands. 



Dr. W. G. Ridewood records (vol. iii., part 2), from 

 off Adelie Land and Queen Mary Land, four species 



NO. 2577, VOL. 103] 



of Cephalodiscus^ — hodgsoni, nigrescens, solidus, and 

 densus — and gives details of the external features of 

 the colonies and notes on the colour and structure 

 of the zooids. For further details of these species 

 reference may be made to Dr. Ridewood 's recent 

 report on the specimens of Cephalodiscus collected by 

 the British Antarctic {Terra Nova) Expedition, a notice 

 of which will appear in another issue of Nature. 



A brief account of the Euphausiacea and Mysidacea 

 is given by Dr. W. M. Tattersall (vol. v., part 5), and 

 of the Cumacea and Phyllocarida by Dr. W. T. 

 Caiman (part 6), 



Prof. A. Dendy (vol. vi., part i) reports on the cal- 

 careous sponges. The Antarctic forms comprise two 

 new species of Leucetta, a new species of Leucandra, 

 and a new variety of Grantia. In the account of the 

 monaxon spicules of a variety of Leucosolenia 

 botryoides from Macquarie Island, Prof. Dendy takes 

 the opportunity of correcting an error in the late Prof. 

 Minchin's well-known memoir on the British species 

 of this genus. Minchin considered that the monaxons 

 of Leucosolenia were separable into two kinds, one 

 very refringent, the other much less so, the refringent 

 monaxons being fevver, straighter, more slender, and 

 having the distal barb less distinct or absent. Prof. 

 Dendy points out that the explanation of these differ- 

 ences is simply that some of the monaxons were 

 viewed as they lay on edge, while others were seen 

 lying flat. 



NEW PROCEDURE AT AMERICAN 

 MA GNETIC OBSER VA TORIES. 

 T N accordance with the usual practice of the United 

 -*■ States Coast and Geodetic Survey, two years, 

 1915 and 1916, are dealt with in the Results of 

 Observations at the magnetic observatories at Sitka 

 and Honolulu, which have recently been published. In 

 previous years the curves were read unsmoothed 

 exactly at the hour local mean time. Commencing 

 with 1915, the hourly value represents the mean 

 ordinate for sixty minutes ending with the hour of 

 the 135th meridian at Sitka (135" 201' W.), and of 

 the 165th meridian at Honolulu (158° 38' W.). The 

 value entered, for instance, under 2h. really belongs 

 to i-5h. Diurnal inequalities continue to be given, 

 as in the past, only for loq (quiet) days a month 

 chosen locally, and for the 5q (international quiet) 

 days, but hourly means are given for all days. The 

 adoption of mean ordinates instead of instantaneous 

 readings is in accordance with what is now 

 probably the usual practice. Unless it is fol- 

 lowed, all-day diurnal inequalities for disturbed 

 months are apt to be very ragged. But the 

 adoption of means for sixty minutes ending at the 

 hour, instead of sixty minutes centring at the hour, 

 is a practice not generally followed except in Ger- 

 many. Even if the procedure had distinct advantages 

 over the ordinary one, its spasmodic adoption by indi- 

 vidual observatories or in individual countries has the 

 serious drawback of introducing diversity where uni- 

 formity is desirable. This is especially true of the 

 international quiet days, the special object of _ which 

 IS to supply exactly corresponding data from different 

 observatories. 



The advantage claimed for the new procedure is that 

 it makes the day self-contained, whereas with the 

 ordinary procedure the values for the first and last 

 midnights depend, one on the last half-hour of the 

 previous day, the other on the first half-hour of the 

 following day. This argument has much weight in 

 the case of elements like rainfall or duration of sun- 

 shine, where we deal with aggregates. But in the 

 case of magnetism the procedure does not really make 



