December 2, 1909] 



NATURE 



137 



the other hand, has no need for such shelters — and perhaps 

 food-supplies — as the pine needles which form its food are 

 always obtainable in abundance. 



The November number of the American Naturalist opens 

 with the first part of an instructive article, by Mr. Newton 

 Miller, on the life-history and habits of the American toad, 

 this article being written to illustrate the proper way of 

 studying common .American animals from the point of view 

 of their position as active forces in the economy of nature. 

 After devoting a considerable amount of space to the 

 breeding-habits and development of the species, the author 

 makes the (to us) novel observation that " toads are more 

 numerous in and about towns than elsewhere. Very rarely 

 is a toad seen in a large field under cultivation. Only 

 fifty toads were seen during a whole season on one 

 thousand acres of farming land in central Indiana. This 

 scarcity may be accounted for by two factors, i.e.^ first 

 that pasturage and tillage kill the toads, or, secondly, that 

 the extensive drainage has exterminated the toad by 

 depriving it of breeding places." 



Mutation in Ceratium, a protozoan common to fresh 

 and salt water, forms the subject of No. 13 of vol. Hi. 

 of the Bulletin of the Museum of Comparative Zoology at 

 Harvard College. After describing the mutations observed, 

 the author, Mr. C. A. Kofoid, states that the most 

 important fact in the phenomena is the abrupt and com- 

 plete change in form in a line of descent in a single 

 generation, or at most in two generations, of organisms 

 asexually produced. The change is recorded in fixed 

 skeletal parts which clearly show the transmutation in 

 shape, while the accessory phenomenon of chain-formation 

 enables the line of descent to be accurately traced. These 

 changes do not give rise to new types, " but old well- 

 known types give rise suddenly to others old and well 

 known, or at least previously known. The particular 

 category to which these types are referred, species, sub- 

 species, varieties, or forms, is a subordinate matter. . . . 

 The fact remains that like gives rise to unlike, that the 

 descendants differ profoundly from the ancestral type." 



Prof. Hickson and Mr. Wadsworth give an interesting 

 account in the Quarterly Journal of Microscopical Science 

 (vol. liv., part ii.) of their observations on Dendrosoma 

 radians. This remarkable Acinetarian occurs in abund- 

 ance on the stems of Cordylophora in the Bridgewater Canal 

 near .'\ltrincham, and supplies were also obtained from 

 Birmingham. The authors give a detailed account of the 

 minute structure of the adult and the formation and 

 development of the ciliated gemmule. They find that the 

 so-called " e.xternal buds " described by Saville Kent are 

 really epizoic Acinetarians of the genus Urnula. The 

 phenomena of conjugation have not yet been observed. 



The Quarterly Journal of Microscopical Science (vol. 

 liv., part ii.) contains a continuation of Mr. Goodrich's 

 well-known researches on the structure of the excretory 

 organs in Amphioxus. Mr. Goodrich brings forward what 

 appears to be very conclusive evidence in favour of his 

 view that the nephridia of Amphioxus do not open, as 

 Boveri has supposed, into the coelom, but end blindly at 

 their inner extremities. He maintains the homology of 

 these organs with the nephridia of Annelids and Platy- 

 helminths, and not with the kidney tubules of the 

 Craniata, and gives a partial, but very interesting, account 

 of their development. He has examined the sections 

 upon which M. Legros based his conclusions as to the 

 origin of the nephridia from the cceloraic epithelium, but 

 does not agree with this author on this important point. 

 We are left to conclude that the nephridia of Amphioxus 

 NO. 2092, VOL. 82] 



are probably ectodermal in origin, although the question 

 is not discussed in detail at present. The paper also deals 

 with the structure known as Hatschek's nephridium, and 

 the discovery of solenocytes in this organ by Goldschmidt 

 is confirmed. It appears to be a true nephridium, homo- 

 logous with the posterior nephridia, but the fact that it 

 opens into the alimentary canal (externally ; it has no 

 internal opening) remains unexplained. We must also 

 direct attention to the valuable criticism of Prof. 

 Hubrecht's views on the early ontogenetic phenomena in 

 mammals, by Mr. Richard Assheton, which concludes the 

 number. 



In a pamphlet recently published at Athens under the 

 title of " 'ludvvns AafxapK koI rb (pyov aiirov/' the author, 

 M. Athanasios E. Tsakalotes, gives a very clear and 

 impartial account of Lamarck's life and work. Passing 

 in brief review the facts and dates of the famous French 

 naturalist's scientific career, he enumerates the various 

 systematic treatises that came from his pen, and enlarges 

 on the evolutionary views which found expression in the 

 " Philosophie Zoologique," published just one hundred 

 years ago. The main points in Lamarck's theory of 

 descent are well brought out — his belief in the continuity 

 of the process, his consequent rejection of Cuvier's theory 

 of successive catastrophes, his doctrine of the inherited 

 effects of use and disuse, and of the direct action of the 

 environment on plants and on the lower animals. The 

 author shows how intimately in Lamarck's mind the facts 

 of adaptation were connected with the problem of evolu- 

 tion ; the passage in the " Philosophie Zoologique " on the 

 relation of structure to habit and function in the three- 

 toed sloth might, he asserts, have been written by Darwin 

 himself. That Lamarck's views failed to commend them- 

 selves to his scientific contemporaries was, the author 

 thinks, partly his own fault ; for the reasons that he was 

 in too great a hurry in reducing his speculations to a com- 

 plete system, and that he weighted his theory with improb- 

 able psychic elements, for example, the alleged influence of 

 individual volition. The author might have added that 

 Lamarck lacked the touch of genius that led Darwin and 

 Wallace to find in natural selection the key to the problem 

 of adaptation. 



Mr. Carus-Wilson informs us that he has sent to the 

 Kew Museum the specimen of oak in which stones are 

 embedded, referred to in his recent paper on " The Natural 

 Inclusion of Stones in Woody Tissue," described in Nature 

 of November 25 (p. 117). 



The development of the embryo-sac of Datisca cannahina 

 forms the subject of an article by Dr. W. Himmelbaur 

 in the Sitsungsberichte der Kaiserlichen Academie der 

 Wissenschafien, Vienna (vol. cxviii., part ii.). One 

 division of the embryo-sac mother cell is the rule ; other- 

 wise, except for the early disappearance of the antipodal 

 cells, development is normal. The author refutes the 

 possibility of parthenogenesis, but finds that partheno- 

 carpy, i.e. the maturation of the fruit without fertilisation 

 of the ovule, may occur. 



A STUDY of trichomes as hereditary characters in a few 

 pure and hybrid species of Juglans, Oenothera, Papaver, 

 and Solanum, is described by Dr. W. A. Cannon in Publi- 

 cation No. 117 of the Carnegie Institute of Washington. 

 It is apparent that the trichomes in these cases are not 

 allelomorphs ; in fact, they vary in size as much accord- 

 ing to their position on the leaves as they do for different 

 species. The development of the hairs on the leaves was 

 also investigated for the species of Juglans, and found 

 to be consistently uniform except in a single type observed 

 in an F^, or second hybrid generation. 



