Page:Science vol. 5.djvu/562

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��ness in details is ns clcarlj' apjiftrent in every one of the sharp and terse deliuiliona. These present the few characteristics whiuli apply to the whole group, and only that gi^sup, rarely extend be3-ond three lines, and are espresaed in words as well chosen as the eharacteristica themselves. As the student follows them from type lo family, he sees clearly that the animal kingdom is really a cosmos, not the chaos which is presented in too many of our zotilogies. Under each type, class, and order, each or- ganic system, the embryonic development, and the habits of the group are described in the same clear, brief terms. Thus one can study the fourteen hundred pages of the • Gmndziige, ' or the eight hundred of the ' Lehrbuch," and scarcely erase five words to a pnge, or con- dense in any may the sentences, without en- tirely changing their meaning. How many thorns would be removed from the path of the working zoologist if all our writers could borrow Professor Claus's sharpness of vision, and accuracy of description !

The general part of the work covers a hun- dred and eighty pages. Of these, a hundred and thirty are devoted to the general qualities of protoplasm, the atmoture and development of cells and tissues, the general anatomy and physiology of each 'compound OT^an,' and embryonic development. The nest fifty pages oonlain in brief outline the history of the science, and the discussion of the theory of evolution. This is, unlike most zoologies, perhaps the most interesting and striking ijor- tion of the book, especially as in this part the genius of the author, in the choice and arrange- ment of material, is the plainer because of the greater liberty here possible. As specially interesting, might be noticed the author's views of parthenogenesis (p, IOC) as a reproduc- tion, on the part of agamic females by true e^a, •' by no moans to be relegated to the category of germ-cells," — views quit* op- posed to the quotations from English writers so common in our American literature, although Professor C'laus seemed to be supported by Balfour and a majority of the German school.

Under Protozoa in the special part, the Monera are disregarded aa a separate group, and merged with Rhizopoda and Flagellata. Thus neither nucleus nor pulsating vesicle ia considered a necessary characteinstio of Rhizo- poda. The Flagellata are provisionally classed under the Infusoria, with expressed doubts of their animal character. Among the Flagellata are reckoned the Astasiadae (Euglena) and the Volvocinidac, although the close alliance of the latter family to the Algae is clearly

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��acknowledged. In an appendix to the Pro- tozoa, the Bacteria and Gr^arinidae are briefly considered. It is an open question whether this is an improvement on the arrangement of forms in the ' Grundziige,' where Bacteria, Flagellata, Myxomycetea, Catallacta. and Labj'rinLhuIeae are all diacussed in connection with Protozoa, but aa groups of very doubtful position and affinities.

The study of the Coelentersta is introduced by a description of the three individual tyjies, polyp, medusa, and ctenophore. The dis- cussion of their resemblances and differences brings the different forms of this group clearly before the student at the outset, beside ftir- nishing him a basis for their classification. The sponges are considered as merely a sul>- group oF Coelenterata.

On account of its embryou Balanogiosaus is assigned to the end of the echinoderms.

Under Vermes the Nemertini are still re- tained with the Piatyhclminthes. The Gephy- rea are placed between the Chaetopoda and Hirudinea as the second sub-class of Aonelidat while the Rotatoria form the fourth and last class of Vermes. This ia certainly an ex- tremely practical classification, even though some might prefer to consider the Rotatoria earlier in the series of worm-forms, on account of their general afGnities.

The second volume contains, 1". Mollnsca; 2", Molluscoidca, to which are reckoned onlj Polyzoa and Brachiopoda as iwaaessing strong affinities to annelids oa well aa Molluaca; 3', Tunicata ; and, 4°, Vertebrata. Thus over flva hundred pages of the two volumes arc devoted to Invertcbrata. The seven hundred flgiirea are well chosen, and far above the average id beauty and clearness. Under every type and class are references to the latest and literature on the subject. The translator haa bad a difficult task. It is no easy matter translate into idiomatic Kuglisli tlie autbor'i condensed and pregnant sentences, where ev word ia imj)orlaut. A few cases might noticed where the rendering of ainglc worda might be improved ; but, as far as can be judged from a careful comparison of about thirty pages taken at random through the work, even such cases are rare, and in general the translation certainly gives a very just ren- dering of the author's ideas.

The publishers have given ua a good pa^ and paper, and clear type. Altogether, it is the only really satisfactory mai^al wbich we have iu Eugliah, and one which no teacher or student of zoology can afford not to posseaa,

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