Septembee 14, 1900.] 



SCIENCE. 



405 



instruction, but will extend to the reference 

 libraries of many professional zoologists. 



Number II., by Mr. J. Johnstone, is on Car- 

 diuni ; and number III. , by H. C. Chadwick, is 

 on Echinus. The former contains 84 pp. and 7 

 pis. ; the latter 28 pp. and 5 pis. 



In Cardium the sections, ' General Organiza- 

 tion, Mantle and Foot,' 'Shell,' 'Alimentary 

 Canal,' 'Branchia,' 'Vascular System,' and 

 'Course of the Circulation,' are particularly 

 well done. One rarely finds in works on the 

 lamellibranchs of the general scope and purpose 

 of this the crystalline style and the method of 

 extending the siphons and foot better treated 

 than here. The renal, nervous and reproduc- 

 tive systems do not fare quite so well, rela- 

 tively. The histology of the nervous system, 

 for example, is not touched upon at all, while 

 it is entered into with some detail for all the 

 other systems. 



The treatment of the renal system is some- 

 what deficient in illustration, and consequently 

 lacks to some extent in clearness. And here 

 one wonders why the terms ' organ of Bojanus ' 

 and nephridia, so well established in lamelli- 

 branch morphology, are not even mentioned. 



The absence of any reference to the coelon, 

 at least under that name, is strange. 



A feature of this particular monograph, and 

 one which will undoubtedly both extend and 

 enhance its local value, is an appendix on 

 ' The Economy of the Cockle, with special refer- 

 ence to the Lancashire Sea-Fisheries District.' 



The Echinus, though perhaps not reaching at 

 any point quite so high a level of descriptive 

 excellence as does Cardium in a few sections, is 

 more even. It is good throughout. 



Both monographs contain much evidence that 

 their authors have not only a large fund of 

 first-hand knowledge of their subjects, but have 

 also wide acquaintance with the original litera- 

 ture bearing upon them. 



One constantly wishes that zoological treatises 

 of this general type might contain more physi- 

 ology and natural history with the morphol- 

 ogy than they do ; but here the desiderata 

 are usually beyond the power of the authors to 

 remedy. The three numbers of this series thus 

 far put out are certainly less defective in this 

 way than are many general works. 



None of the numbers thus far issued have 

 either tables of contents or indexes, and they 

 should certainly have both ; their value would 

 be greatly enhanced thereby. 



I would again express regret that the vol- 

 umes cannot be more securely bound. A num- 

 ber' of forms in the copy of Cardium that has 

 come into my hands are now nearly ready 

 to fall out, and the book has had no hard usage. 

 The educational worth of the books certainly 

 ought to insure them a place in many labora- 

 tories and reference libraries ; and their useful- 

 ness ought not to be impaired by defective con- 

 struction. 



Wm. E. Ritteb. 



SCIENTIFIC JOURNALS AND ARTICLES. 



Popular Astronomy for August and September, 

 published at Northfield, Minn., contains, as 

 leading articles, views of some prominent as- 

 tronomers, about the present opposition of the 

 planet Eros as favorable for a study of this new 

 planet's parallax. If its parallax can be ob- 

 tained, micrometrically and photographically as 

 accurately as is now believed, the result will 

 help to a better knowledge of the solar parallax. 

 Such knowledge would improve most of the 

 constants of the solar system. S. J. Brown, 

 Astronomical Director of the United States 

 Naval Observatory, has prepared the first and 

 second articles. The first is on the feasibility 

 of obtaining the solar parallax from simultane- 

 ous micrometric observations of Bros, and the 

 second is a translation from the French of two 

 circulars issued by the International Astro- 

 photographic Conference at its meetings in July 

 and August last, giving instructions to all the 

 astronomers of the world who are expected to 

 co-operate in observing Eros during Septem- 

 ber and October. Director Brown gives useful 

 comments on these circulars. Other articles 

 are : 'Ptolemy's Theorem on the apparent En- 

 largement of the Sun and Moon near the 

 Horizon,' by Dr. T. J. J. See, Washington, D. 

 C; 'Total Eclipse of May 28, 1900,' by Pro- 

 fessor M. Moye, University at Montpellier, 

 France ; an illustrated article on the same sub- 

 ject by the editor; 'The Propagation of the 

 Tidal Wave,' by Dr. T. J. J. See ; ' The Planet 

 Jupiter,' by G. W. Hough, and an obituary 



