244 



SCIENCE 



[N. S. Vol. XLIII. No. 1103 



satisfy ourselves about our own weaknesses. 

 The responsibility is nicely divided; it is just 

 as much the duty of the students to learn as 

 of the lecturer to teach, and neither student 

 nor teacher has the material for a considered 

 judgment upon the matter. That is why the 

 " hobby " system, with occasional rewards for 

 exceptional success, is so popular. It can be 

 worked best by letting things go their own 

 way. 



The present state of things, which all agree 

 in deploring, can be altered by drawing a clear 

 distinction between a society's hobbies and the 

 nation's purposes, and entrusting them to 

 separate administrative management. Mr. 

 Carnegie has made it clear that the financial 

 detachment of a voluntary society is not essen- 

 tial to the successful organization of scientific 

 research. — F. E. S. in Nature. 



SCIENTIFIC BOOKS 



Studies in Edrioasteroidea. I.-IX. By F. A. 

 Bather. Published by author at " Tabo," 

 Marryat Eoad, Wimbledon, England, Octo- 

 ber, 1915. Pp. 136, 13 plates. Price 10s. 

 This book by the well-known authority on 

 echinoderms contains a series of articles that 

 were published from 1898 to date in the Geo- 

 logical Magazine, but of which no separata 

 were distributed because the plates were lost 

 while in store. In consequence of this unfor- 

 tunate circumstance several authors, the pres- 

 ent writer among them, have become guilty of 

 ignoring important results of Dr. Bather's 

 studies. 



The earlier papers contain elaborate descrip- 

 tions of all known Edrioasteroidea based on so 

 careful preparation of specimens that months 

 were spent in several cases in cleaning a single 

 specimen. By this method the finest details, 

 notably in our North American Edrioaster 

 higshyij were brought out, such as the hydro- 

 pore and the small plates of the periproct. 

 Three new genera are distinguished, but most 

 important are the three concluding articles, 

 published in 1915, which contain the morphol- 

 ogy and bionomics of the Edrioasteroidea, a 

 comparison of their structure with that of the 

 Asterozoa, and a discussion of the genetic rela- 



tions to other Echinoderms. In these chapters 

 Dr. Bather not only succeeds in demonstrating 

 much closer resemblances between these early 

 pelmatozoans and the Asteroidea than were 

 hitherto suspected, but also in tracing the 

 probable course of derivation of the Asteroids 

 from the Edrioasteroidea. These conclusions 

 give the work a distinctive value for all stu- 

 dents of phylogeny. 



The book is finely illustrated with diagrams 

 and a dozen plates of good photographs and 

 very lucid drawings. Eudolp Euedemann 



New York State Museum 



SPECIAL ARTICLES 



ADAPTABILITY OF A SEA GRASS 



While dredging during July, 1915, in the 

 Gulf of Mexico near the Dry Tortugas on the 

 Carnegie Institution's yacht, Anton Dohrn,tb.e 

 writer's attention was attracted to two com- 

 paratively rare plants. These plants, which 

 are species found only in the western hem- 

 isphere, were remarkable not only for their 

 curious and interesting morphology, but rather 

 for the unusual conditions under which they 

 were found growing. Although spermato- 

 phytes, these plants came up in the dredges 

 with marine algas from a depth of sixteen to 

 eighteen fathoms, i. e., ninety-six to a hundred 

 and eight feet. The algse associated with 

 them were the usual species found in those 

 waters, viz., Caulerpa, Halimeda, Penicillus, 

 Codium, Udotea, Acetaiularia, etc. Bottom 

 samples taken with a clasper on the sounding 

 instrument showed the Gulf floor here to con- 

 sist of a fine white mud composed of calcare- 

 ous debris such as broken corals, molluscan 

 shells and echinoderm tests. 



All the plants were carefully picked out of 

 the miscellaneous material which came up in 

 the dredges and preserved. These on being 

 later brought north were identified by the 

 writer as two species of Halophila du Petit 

 Thouars, and the only members of the genus, 

 as remarked above, to be found in North or 

 South America, and belonging in the order 

 Hydrocharitales. A brief description of these 

 two species is given as they have a limited 

 range in the tropical waters of the western 



