August 21, i8gi.J 



SCIENCE. 



109 



is the shoal channel which separates the South Shetlands from 

 Cape Horn, which is a region of great snowfall. Therefore should 

 the antarctic ice gain sufficient thickness to rest on the bottom of 

 this shallow sea it would move into the Cape Horn channel and 

 eventually close it. The ice growth would not be entirely from 

 the southern continent, but also from lands in the i-egion of Cape 

 Horn. Thus the antarctic continent and South America would 

 be connected by an isthmus of ice, and consequently the indepen- 

 dent circulation of the Southern Ocean arrested. Hence it will 

 be seen that the westerly winds, instead of blowing the surface 

 waters of the Southern Ocean constantly around the globe, as they 

 are known to do to-day, would instead blow the surface waters 

 away from the easterly side of the ice-formed isthmus, which 

 would cause a low sea-level along its Atlantic side, and this low 

 sea-level would attract the tropical waters from their high level 

 against Brazil well into the southern seas, and so wash the antarc- 

 tic continent to the eastwai-d of the South Shetlands. 



The tropical waters thus attracted southward would be cooler 

 than the tropical waters of to-day, owing to the great extension 

 of cold in the southern latitudes. Still they would begin the slow 

 process of raising the temperature of the Southern Ocean, and 

 would in time melt the ice in all southern lands. Not only the 

 Brazil currents would penetrate the southern seas, as we have 

 shown, but also the waters from the high level of the tropical In- 

 dian Ocean which now pass down the Mozambique Channel would 

 reach a much higher latitude than now. 



The ice- made isthmus uniting South America to the antarctic 

 continent would, on account of its location, be the last body of 

 ice to melt from the southern hemisphere, it being situated to the 

 windward of the tropical currents and also in a region where the 

 fall of snow is great ; yet it would eventually melt away, and the 

 independent circulation of the Southern Ocean again be established. 

 But it would require a long time for ice-sheets to again form on 

 southern lands, because of the lack of icebergs to cool the southern 

 waters. Still, their temperature would gradually lower with the 

 exclusion of the tropical waters, and consequently ice would slowly 

 gather on the antarctic lands. 



The above theory thus briefly presented to account for the cli- 

 matic changes of the high southern latitudes is in full accord with 

 the simple workings of nature as carried on to-day ; and it is proba- 

 ble that the formation of continents and oceans, as well as the 

 earth's motions in its path around the sun, have met with little 

 change since the cold era iced the lands of the high latitudes. 



At an early age, previous to the appearance of frigid periods, 

 the ocean waters of the high latitudes probably did not possess an 

 independent circulation sufficient to lower the temperature so that 

 glaciers could form. This may have been owing to the shallow 

 sea-bottom south of Cape Horn having been above the surface of 

 the water, the channel having since been formed by a compara- 

 tively small change in the ocean's level. For, while considering 

 this subject, it is well to keep in mind that whenever the western 

 continent extended to the antarctic circle it prevented the inde- 

 pendent circulation of the Southern Ocean waters, consequently 

 during such times ice periods could not have occurred in the 

 southern hemisphei'e. 



It will be noticed that according to the views given above, the 

 several theories which have been published to account for great 

 climatic changes neglect to set forth the only efficacious methods 

 through which nature works for conveying and withdrawing 

 tropical heat sufficient to cause temperate and frigid periods in 

 the high latitudes. While lack of space forbids an explanation of 

 the causes which would perfect an ice period in the northern 

 hemisphere, I will say that it could be mainly brought about 

 through the independent circulation of the arctic waters, which 

 now largely prevent the tropical waters of the North Atlantic 

 from entering the arctic seas, thus causing the accumulation of 

 ice sheets on Greenland. But before a northern ice period can be 

 perfected, it seems that it will need to co-operate with a cold period 

 in the southern hemisphere ; and in order to have the ice of a 

 northern frigid period melt away, it would require the assistance 

 of a mild climate in the high southern latitudes. 



0. A. M. Taber, 

 Wakefield, srass., Aug. 14. 



BOOK-REVIEWS. 



The Journal of the College of Science, Imperial University of 

 Japan. Vol. IV., Part I. 



Tms volume forms a fitting complement to the numbers already 

 issued, and indicates the advanced position of the college and the 

 high standing of its teachers and special students. If any thing 

 would commend an institution to the generous attention of the 

 government it is the admirable work which has been embodied in 

 the various memou-s of the series. The present number opens 

 with a memoir by Professor K. Mitsukuri on the " Foetal Mem- 

 branes of Chelonia." It is one of a series on the embryology of 

 Reptilia. The first one, in which Mr. Ishikawa was joint author, 

 was on the germinal layers of Chelonia. The foetal membranes 

 of Reptilia have been supposed to bear a close resemblance to 

 those of birds. Mr. Mitsukm-i has found many notable features 

 which have, hitherto, been overlooked, and these appeared so re- 

 markable that he has made them the subject of his memoir. Ten 

 beautiful plates accompany the text. 



Mr. Kamakichi Kishinouye gives the results of his researches on 

 the " Development of the Araneina," illustrated by four plates. 

 The material for study was obtained on the grounds of the univer- 

 sity, and this included Lycosa, Agalina, and other genera of 

 spiders. His method of treating the eggs is given in full, and will 

 be found of great value to the student. His discussion of the 

 formation of the pulmonary lamellse or lung-book is very interest- 

 ing. He thinks it probable that the lung-book was derived from 

 the gills of some aquatic arthropodous animal, such as Limulus, 

 comparing it with the lamellar branchia of Limulus sunk beneath 

 the body surface. He shows that an invagination of the first ab- 

 dominal appendage gives rise to the lung-book, and a similar in- 

 vagination at the base of the second gives rise to a tube — abortive 

 trachea. Many other interesting points are developed or sustained 

 in this memoir. 



Mr. Oka has a memoir on a new species of fresh-water polyzoa, 

 Pectinatella gelatinosa. His methods of preparation wiU be found 

 valuable to students of this group. His allusions to the views of 

 Hyatt and Morse as to the anterior region of the polypidae refer to 

 views uttered over twenty-five years ago, when the polyzoa and 

 brachiopods, with the tunicates, were supposed to be moUuscan. 

 These views are antiquated, and have long since been abandoned 

 by the authors in question. Circulation is showed by Oka to be 

 by ciliary action. He confirms Verworn in showing ciliary action 

 on the external wall of the alimentary canal. Important obser- 

 vations are made on a pair of excretory organs which are ciliated 

 and communicate with the epigastric cavity by wide openings. 

 Their external openings have not been found, but the relation 

 these bear to the segmental organs of brachiopods and worms 

 seems unquestionable. An exhaustive discussion is given to the 

 development of the statoblast, and the longitudinal sections de- 

 picted are of great value. The memoir is a solid contribution to 

 the literature of this interesting group of animals. Four plates 

 illustrate the details of anatomy and development. 



Mr. Seitaro Goto has a memoir, with three plates, on a new 

 form of Diplozoon, to which he gives the specific name of " nip- 

 ponicum." He gives reasons for separating it from the single 

 species known as paradoxum. The curious creature is described 

 in detail, and interesting points are added to what has already 

 been known. 



A new species of hymenomycetous fungus injurious to the mul- 

 berry tree, illustrated by four plates, is described by Mr. Nobujiro 

 Tanaka, with a discussion of this fungus, which has caused much 

 destruction of the mulberry tree in Japan. 



Notes on the irritability of the stigma, by Mr. Miyoshi, are illus- 

 trated by two plates. The author shows conclusively that this 

 irritability, as Hermann Miiller first suggested, has to do with the 

 cross-fertilization of the flower, and is not for protection against 

 wind and rain. Irritabflity is excited by an insect or a bristle, and 

 not by a drop of water or by blowing against it. 



Notes on the development of the suprarenal bodies in the mouse, 

 with two plates, are by Mr. Masamaro Inaba. In this paper is 

 discussed the mode of origin of the two substances which go to 

 make up the suprarenal bodies. He comes to the conclusion that 



