170 



NA TURE 



[December 22, 1904 



point of which is the minute adaptations of structure 

 to function, an illustration of a kind of research which 

 is always welcome and valuable. 



\V E. Ritter discusses the structure and affinities 

 of a new type of Ascidian from the Californian coast, 

 which he ' calls Herdmanin after a well known 

 ascidiologist. The colony is composed of crowded but 

 entirely free zooids arising by budding from short 

 much branched, closely interwoven stolons. The zocid 

 is long and narrow, with three regions-thoracic, 

 digestive, and cardiogenital. It is quite unique m 

 having two epicardiac tubes, separate throughout their 

 length; the oviduct serves as a uterus in which the 

 embryos go through their development to nearly the 

 period of metamorphosis; there is a peculiar grouping 

 of the numerous branchial tentacles. It seems to be 

 a divergent offshoot from the Polyclinid branch. 

 R M. Strong brings us back to a familiar subject and 

 an old problem; he analyses the iridescence or metallic 

 coloration of the dorsal surfaces of the distal portions 

 of the feathers from the sides of the neck of grey 

 domestic pigeons. The coloration is not due to diffrac- 

 tion and Gadow's refraction-prism hypothesis will not 

 work The colours are probably thin-plate interference 

 colours or Newton's rings, effects which are produced 

 where spherical pigment granules come in contact with 

 the outer transparent layer. C. R. Eastman takes 

 us back to Palaeozoic sharks, showing that the much- 

 debated Edestus fossils are genuine teeth, and repre- 

 sent a stage in an interesting evolution series from 

 Campodus to Helicoprion. We can hardly do more 

 than refer to H. V. Neal's careful study of the de- 

 velopment of the ventral spinal nerves in Selachians, 

 but we may note that while the neuraxones of these 

 nerves develop like those of .\mniota as processes of 

 neuroblast cells, there is a migration of medullary cells 

 in earlv stages of development, which, though they 

 take no part in the formation of the neuraxones or 

 cranglia of the ventral nerves, participate in the form- 

 ation of the nerve-sheaths, which have usually been 

 regarded as of mesenchymatous origin. 



H S Jennings elaborates his interesting thesis 

 that the asvmmetrv of most flagellate and ciliate In- 

 fusorians, as also of the Rattulid Rotifera, is corre- 

 lated with the habit of swimming in spirals. The 

 spiral course is the simplest device for permitting an 

 unequallv balanced organism to progress in a given 

 direction through the free water, and the method of 

 reaction to most stimuli is closely correlated with the 

 unsymmetrical or spiral type of structure. Rolfe 

 Yorke contributes a study of the nerve cells of the cock- 

 roach and of the substance within these that seems to 

 correspond to the chromophilous material in the nerve 

 cells of higher animals. R. M. Yerkes shows by 

 elaborate experiments that Daphnxa pidex is strongly 

 positively phototactic to all intensities from o to loo 

 candle-power, and is negatively thermotactic at a 

 temperature of about 28° C. 



In a very interesting paper on Mendel's law and the 

 heredity of albinism, W. E. Castle and G. M. Allen 

 show that complete albinism, without a recorded ex- 

 ception, behaves as a recessive character in inherit- 

 ance, and that the facts are in general accord with 

 NO. 1834, VOL. 71] 



Mendelian principles. P. E. Sargent discusses the 

 structure and functions, development and phylogeny 

 of that archaic portion of the mesencephalic roof known 

 as the torus longitudinalis which is characteristic of 

 Teleosts. T. G. Lee attacks a not less difficult problem 

 — the implantation of the ovum in the gopher, which 

 he finds to be quite unique as regards the nature and 

 history of the pre-placcntal " fixation-mass " formed 

 by the trophoblast. J. H. Gerould makes a comparison 

 of the early stages of Sipunculus and Phascolosoma, 

 and seeks to show that the " serosa " of the former re- 

 presents the remains of a degenerating prototroch equi- 

 valent to that of the latter, which is in turn homo- 

 logous with the primitive condition seen in mesotrochal 

 .Annelids. 



G. H. Parker takes us once more into the open air 

 in his study of the positive and negative phototropism 

 of the mourning-cloak butterfly (Vanessa antiopa). It 

 is interesting that the negative phototropism is only 

 seen in intense sunlight and after the butterfly has 

 established a certain state of metabolism by flying 

 about for a while, and that the position assumed in 

 negative phototropism exposes the colour patterns of 

 the wings to fullest illumination, and has probably 

 something to do with bringing the sexes together 

 during the breeding season. Ida H. Hyde presents 

 a new interpretation of the structure of the eye of 

 Pecten, supplementing and correcting previous de- 

 scriptions. The long series of memoirs ends with one 

 by H. B. Ward on the lar\-se of Dermalobia hominis 

 — an Oestrid or bot-fly, widely distributed in America, 

 though not in the States, which occurs commonly in 

 the skin of cattle, pigs, and dogs, and less frequently 

 in some other creatures, including — unfortunately — 

 man. 



We cannot conclude our rapid review of this huge 

 volume without directing attention to the great range 

 of zoological territory which the memoirs cover, to the 

 high standard of workmanship which they exhibit, and 

 to the unanimity with which the various authors 

 recognise their indebtedness to their master, Edward 

 Laurens Mark. J. A. T. 



(I 



SYNTHESIS OF VITAL PRODUCTS. 

 The Chemical Synthesis of ]'ital Products, and the 

 Inter-relations between Organic Compounds. By 

 Prof. Raphael Meldola, F.R.S. Vol. i. Hydro- 

 carbons, Alcohols and Phenols, .•\ldehydes, Ketones, 

 Carbohydrates and Glucosides, Sulphur and 

 Cyanogen Compounds, Camphor and Terpenes, 

 Colouring-matters of the Flavone Group. Pp. 

 xvi + 338. (London : E. Arnold, 1904.) Price 21s. 

 net. 



IN spite of the long and daily increasing list of 

 successful chemical syntheses of substances which 

 are primarily produced as the result of processes 

 occurring in living organisms, one constantly hears 

 from physiologists the complaint that the synthetic 

 work of chemists, wonderful as it may be in itself, 

 throws no light on the biochemical problem of how 

 the same substances are generated in the bodies of 

 pl.-mls or animals. The points of view of the organic 



