July 12, 1917] 



NATURE 



399 



Leny grits to the north-west. — Mary G. Haseman : 

 Knots with a census of amphicheirals with twelve 

 crossings. This discussion followed the lines lai<l 

 down by Tait in his papers on knots. There were new 

 theoretical developments facilitating the study of knots 

 of higher orders. There were found to be sixty-one 

 amphicheiral knots of twelve crossings. Tait had 

 already given the amphicheirals ot lower order, 

 namely, one four-fold, one six-fold, five eight-fold, 

 and thirteen ten-fold. 



June 18.- — Dr. J. Home, president, in the chair. — 

 Prof. G. Kerr : Note upon an observation on insects 

 and light. This was a description of the manner in 

 which a number of Homopterous insects alighted on 

 the page of an open book in the neighbourhood of an 

 artificial ligiit, each insect rapidly adjusting itself 

 so that its two eyes were equally exposed to the light. 

 As each insect was picked ofT its position was marked 

 by a short pencil stroke in the direction of its long 

 axis. Had the insects been flying during this orienta- 

 tion they would have flown straight towards the light. 

 This record, which had been made twenty-one years 

 ago in South America, had only recently been re- 

 covered. It was a simple illustration of the way in 

 which heliotropism is produced in animals of bilateral 

 symmetry-, the tendencv being for the eyes to get into 

 positions of equal stimulation, so that the direction of 

 motion is towards the source of light. — Discussion on 

 the simplification of the calendar. In opening this dis- 

 cussion Mr. A. Philip suggested modificatidns which 

 would divide the year into four three-monthly quarters 

 of ninet\--one days, and yet would in no way interfere 

 with the position of Easter and the rulesby which it 

 was determined. There would thus be complete his- 

 orical continuity with the Gregorian calendar. The 

 suggestion was to take one day from August and add 

 it to the following Februan,-. By subsequent exclu- 

 sion, say, of May 31 from the succession of weekdays, 

 and the addition of another similar day in leap-years, 

 a perpetual calendar would be at once obtained. If, 

 further, the almanac vear began on March i, only 

 one Dominical letter would be required for each year, 

 whether ordinan' or leap-year. 



DuBLiN. 



Royal Irish Academy, June 11. — Sir F. W. Moore, 

 vice-president, in the chair. — Mrs. L. Porter : The 

 attachment organs of the common corticolous Rama- 

 linae. The lichens investigated differ in their mode of 

 attachment to bark from that of others previously 

 described, notably by the German school of licheno- 

 logists. The thallus consists of cortex, gonidial layer, 

 and medulla ; the cortex is composed of longitudinally 

 arranged hyphae. Differentiation of inner and outer 

 cortex, and pseudoparenchymatic appearance of the 

 former, depend chiefly upon the reagents used. Attach- 

 ment organs are strands of hyphae continuous with the 

 cortical tissue. f)enetrating the periderm and branching 

 :n all directions. From these branches, or from the 

 superficial mycelial layer, or from both, new plants 

 arise. The strands may penetrate the living tissues 

 even so far as the wood.— Miss J. Stephens: Report on 

 the sponges collected by the dredging expeditions of 

 the Royal Irish Academy and the Royal Dublin Society 

 off the coast of Ireland. The paper gives a short 

 account of the sponges obtained many years ago by 

 the early dredging expeditions off the west coast of 

 Ireland. The most interesting of these sponges are 

 growing in small, thin encrustations on coral {Lopho- 

 helia i)rolifera). Two species are described as new; 

 one of them belongs to the subgenus Paresperella, of 

 the genus Mycale, and is the first representative of 

 this subgenus to be recorded from the Atlantic Ocean. 



NO. 2489, VOL. 99] 



June 25. — Sir F. W. Moore, vice-president, in the 

 chair. — R. F. Scharff, H. J. Seymour, and E.T. Newton : 



The exploration of Castlepook Cave, Co. Cork (being 

 the third report from the committee . appointed to ex- 

 plore Irish caves). The authors described the results 

 of the exploration of the ver\' extensive chambers and 

 passages of this cave, which is situated within a 

 few miles of Doneraile, Co. Cork. The cave con- 

 tained vast quantities of reindeer remains, two species 

 of lemming, Arctic fox, as well as adult and young 

 mammoths, bears, wolves, Irish elk, and the cave 

 hyaena. The bird bones seem to have been mostly 

 introduced by fox burrows and pitfalls in recent times. 

 The authors express the opinion that the cave is prob- 

 ably of pre-Glacial origin. After an older set of 

 animal remains h-d been deposited in pre-Glacial 

 times, the cave remained practically sealed up until 

 comparativelv recent times, when another, much more 

 modern, fauna found its way into the cave. _ It is 

 conclusively shown that the cave hyaena and reindeer 

 were contemporaneous in Ireland, and that the mam- 

 moth, Irish elk, and bear flourished at the same 

 time. 



Royal Dublin Society, June 26. — Dr. G. H. Pethy- 

 bridge in the chair.— Miss A. L. Massy : The gymno- 

 somatous Pteropoda of the coasts of Ireland. Twelve 

 species are enumerated, taken off the west, south, and 

 east coasts of Ireland. Six species, of which illustra- 

 tions were given, are described as new, and belong to 

 the genera Pneumodermopsis, Spongeobranchaea , 

 Clionopsis, and Cephalobrachia (one each), and Thli- 

 ptodon (two). Four species bel<Higing to the genera 

 Pneumodermopsis (two), Cephalobrachia, and Noto- 

 branchaea have not previouslv been recorded from the 

 British and Irish area.— Prof. T. Johnson : Pterido- 

 sperms from the Upper Devonian beds at Kiltorcan, 

 Co. Kilkennv.— Prof. A. F. Dixon : Note on the frag- 

 ment of the lower jaw from Piltdown, Sussex. 

 Inasmuch as our knowledge of the facial portion 

 of the skull of Piltdown man is derived from 

 a study of the very remarkable fragment found 

 of the lower jaw, it becomes of extreme in- 

 terest to inquire it its ape-like peculiarities have not 

 been over-emphasised in the various proposed recon- 

 structions 01 the entire skull. The author believes that 

 it is possible to reconstruct the lower jaw on more 

 distinctly human lines than has been proposed hitherto. 

 From a comparison with the ijiandible of a Melanesian 

 islander and other specimens from lower existing races, 

 it does not seem necessary to assume that in the Pilt- 

 down man there was (i) complete absence of chin 

 (mental eminence) ; (2) a more parallel arrangement of 

 the pre-molar teeth than in many recent races ; (3) 

 enormous development of the incisor teeth ; or (4) a 

 square-shaped front to the alveolar part of the jaw. 

 Further, it is not necessary to assume so great a 

 degree of prognathism as is shewn in the various 

 reconstructions of the skull that have been published. 

 A reconstruction proposed by the author showed that 

 it was possible that the alveolar part of the Piltdown 

 jaw formed a curve similar to that found in many 

 primitive existing races, and that the mental region 

 mav have been as much developed as in them or in 

 the Neanderthal race. No comparison with recent man 

 or ape can detract from the extreme interest of the 

 lower-jaw fragment from Piltdown, but it is very 

 doubtful if the remarkable features which it exhibits 

 are sufficient to support the claim that Piltdown man 

 belonfred to a e^enus different from modem man, or 

 that he may not have represented an early race of 

 Homo sapiens .from which modern man has been 

 derived. 



