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NA TURE 



[August 3. 189: 



On Saturday a joint excursion was carried out with the 

 Dublin Naturalists' Field Club ; some members of the Belfast 

 Field Club being aUo present by invitation. The whole party 

 drove from Bray up Ben Cree to Loughs Bray, the Rev. Maxwell 

 Close explaining the glacial dam that separates the two lakes, 

 and the moraines in the mountain-hollows round them. The 

 descent was made by the romantic grounds of Luggela, which 

 were kindly thrown open by Mr. Stepney. Here the granite 

 abuts on the metamorphosed Ordovicians, and displays, on 

 Lough Tay itself, a fissile foliated structure of unusual delicacy. 

 On climbing out of the deep hollow to the main road, abundant 

 large erratics of granite, resting on Ordovician schist, were 

 seen on all the moorland slopes. 



On Sunday, July 30, Dr. V. Ball, F.R.3., conducted the 

 party over the geological and antiquarian collections in the 

 Museum of the Science and Art Department, Dublin, Major 

 M'Eniry pointing out the treasures of the Royal Irish Academy 

 collection. 



THE DEVELOPMENT OF ECHINOCYAMUS 

 PUSILLUS.^ 



'T'HE year 1891 will remain memorable to echinologists for 

 ■*• the richness of its products upon the morphology of the 

 class with which they deal, not the least brilliant and far-reach- 

 ing of which is the discovery by Brooks and Field of the pri- 

 mary bilateral symmetry of the water-vascular system of 

 Asterias ; but the following year will not pale beside it, if only 

 on account of the magnificent treatise to which we now call 

 attention. The amount of solid work which the author has 

 compressed into his fifty-seven ^ages is little short of astonish- 

 ing. The monograph is written in excellent English, and 

 illustrated by nine plates well worthy of the text ; and from 

 whatever standpoint it is judged, a verdict of unstinted praise 

 must be given. 



After a short introduclion, the author furnishes an account of 

 his methods, incidentally alluding to a remarkable result 

 obtained by fertilising ova derived from females reared in a 

 dirty locality with spermatozoa obtained from males dredged in 

 the open sea ; and he next proceeds to the detailed consideration 

 of the sexual elements and fertilisation, in the course of which 

 evidence pointing to a possible chemiotaxis is adduced, in 

 what is termed the "attractive forces" of the ova and sper- 

 matozoa. The segmentation of the oosperm is next considered. 

 The author remarks that he has more than once seen very 

 delicate connective filaments crossing the cleavage-cavity from 

 one segment to another at the earliest stages in the formation 

 of the former ; and later on, in dealing with the phenomena of 

 mesenchyme formation, he calls attention to the significant 

 fact that in young gastrula: it is common to find mesenchyme 

 cells "attached by one pseudopodium to the ectoderm, and 

 by another to the archenteron," giving the impression 

 "that they facilitate the process of invagination." Interest- 

 ing as are these facts in their bearing upon the general ques- 

 tion of protoplasmic continuity in the animal body, they fall 

 into insignificance beside that portion of the work which deals 

 with the vital phenomena of segmentation itself. In the course 

 of it the author remarks that when studying the phenomena 

 alluded to "one gets the impression that the segments alter- 

 nately attract and repel each other, and that the highest degree 

 of attraction occurs when the nuclei after a completed segmen- 

 tation have obtained their rounded distinct form and are in a 

 state of repose." This conclusion is reached after extensive and 

 careful observation, and the tendency of current research in 

 cytology appears to us to suggest that the near future may show 

 the author to have herein formulated a general law. 



Dealing next with the blastula and gastrula stages, an apical 

 disc bearing a tuft of long cilia, akin to that of the annelid larva, 

 is described ; and the author, having proved that it has nothing 

 to do with locomotion, provisionally suggests that it may be a 

 larval sensory organ. The formation of calcareous deposits is 

 recorded to first occur during the blastula stage, and the spines, 

 interradial plates, and spherids of the young urchin, are alike 

 traced to a "first indication" in the form of a minute tetra- 

 hedron originated by the agency of mesenchyme cells ; and the 

 author, after full consideration, inclines to the belief the "teeth " 

 also " originate as small tetrahedrons." The detailed observa- 



1 A Monograph, by Prof. Hjalmar Thiel, Nova Acta Reg. Soc. Set. 

 (Upsala; Ser. iii. pp. 1-57. 1892.) 



tions incorporated in this section of the work are of intense in- 

 terest, especially in their bearing upon the attempt of Dreyer 

 to reduce the skeletogenesis of the echinodermata and certain 

 other invertebrated animals to a common principle of purely 

 mechanical origin. 



The young urchin is traced to a "first indication" in an 

 ectodermic invagination of the Pluteus, as previously described 

 by Agassiz and Mentschnikoff, and the author observes that the 

 disc-like sac thus formed becomes differentiated into a " thick- 

 walled bottom," which plays an important part in the develop- 

 ment of the young urchin, and a remaining portion which 

 " only serves as a kind of amnion." 



One very curious and interesting discovery which is announced 

 is that of a choano-flagellated condition of the cells of the ciliated 

 band of the Pluteus, which, in the author's words, "curiously 

 remind one of collar-cells in the Porifera ; " and it is not a little 

 remarkable that this observation should have been closely 

 followed by that of Franze that Biitschli's so-called " mund 

 vacuole" of the Choano-flagellate Infusoria [Codosiga botrytis) is 

 in reality a delicate membrane connecting the collar with a 

 specialised sucking vacuole. 



In his introduction the author confirms the surmise of Johannes 

 Miillerthat certain ofhis (now classical) descriptions of Echinoid 

 larvae were those of Echinocyamus pusillus. and in so doing 

 points out that nobody has in the meantime published anything 

 on the development of that animal. Our appreciation of the 

 excellence and value of the author's work may, perhaps, be best 

 expressed in the assertion that it appears to us in every way 

 worthy of this unique association with that of the great f<mnder 

 of our modern comparative anatomy. 



FRANCE AND INTERNATIONAL TIME. 



T^HREE years ago M. W. de Nordling made a communication 

 to the French Geographical Society with regard to a 

 universal hour. In a further communication to the same society, 

 on April 7> he traces the changes that have been made since 

 1889. The state of things at the present time are summarised 

 as follows : — 



(1) The time of eastern Europe, which differs by only one 

 minute from that of St. Petersburg, is employed in Russia, 

 Roumania, Bulgaria, and Roumelia, to Constantinople. 



(2) The time[of Central Europe prevails in Sweden, Germany, 

 Austria, Hungary, Bosnia, Servia ; and its adoption is assured 

 in Switzerland, Italy, and Denmark. 



(3) The time of Western Europe (Greenwich time) is in 

 use in Great Britain, Holland, and Belgium, and, to complete 

 its European domain, needs the addition of France, Spain, 

 Portugal, and Ireland. 



Witli regard to France, M. de Nordling dwelt on the fact 

 that while civil time is referred to the Paris meridian, the rail- 

 way service runs according to Rouen time, which is five minutes 

 behind Paris time. The French Commission of 1891 remarked 

 upon the absurdity of this system in the following words : — 



" In order that there should be no ambiguity in the use of the 

 uniform hour adopted, it will be necessary to put an end to the 

 curious habit that exists only in France, where two timepieces 

 are seen at all railway stations having between them a constant 

 difference of five minutes. 



" It is useless for the railway companies to say that the in- 

 terior time of their stations concern them particularly, and only 

 refer to their service ; only error and confusion can result from 

 the system. The hours of departure being regulated by the 

 interior clock, there must always be a tendency to consider these 

 indications as the most exact. 



"To our knowledge, in no other country outside our own, is 

 this peculiarity found, which perpetuates an error, and, in fact, 

 puts the trains behind by five minutes." 



"It is said," remarked M. de Nordling, "that the five 

 minutes retardation are regarded with approval by travellers. 



"This was probably true in 1840, when one would only goto 

 Saint-Germain and Versailles, but to-day, when everybody 

 discounts the five minutes, they have lost their virtue, and onijr 

 force the passenger to make incessant calculations. The un- 

 certainty is increased in the buffets, where it is doubtful whether 

 the clock on the wall indicates interior or exterior time. 



" It is not only from a national point of view that this dual 

 hour is vexatious, but also from an international point of view. 

 In fact, it renders our hour absolutely inappropriate to all inter- 

 national usage. Suppose Switzerland had adopted Paris time ; 



NO. 1 240. VOL. 48] 



