I40 NATURAL SCIENCE. August. 



The Brachiopodist's Vade-Mecum. 



An Introduction to the Study of the Brachiopoda, intended as a Handbook 

 for the use of Students. By James Hall, assisted by John M. Clarke. The 

 First Part, issued in Report of the Regents of the N.Y. State Museum, xlv., for i8gi, 

 pp. 450-616. Albany, dated 1892, but published in 1894. 



In our first volume (pp. 628-629) we noticed the important work by 

 Messrs. Hall and Clarke, entitled " An Introduction to the Study of 

 the Genera of Palaeozoic Brachiopoda." The present handbook is 

 practically an attempt to bring the facts and conclusions of that 

 advanced treatise into a form more suited to the pecuniary and 

 intellectual capabilities of the student. Hitherto English-speaking 

 students have either had to struggle with the ponderous tomes of 

 Davidson, issued by the Palaeontographical Society, or, if they wished 

 for some more concise, elementary, and, at the same time, up-to-date 

 account, they have had to overcome the difficulties presented by a 

 foreign language, and to rely on the admirable summaries by Von 

 Zittel in German, and by Oehlert in French. Although, therefore, 

 Professor Hall tells us that " the work has been prepared for the use 

 of American students," we take upon ourselves to assure him that, so 

 soon as it is issued in completed book form, it will win the gratitude 

 of all those English-speaking zoologists and geologists who share with 

 the authors an interest in the Brachiopoda. 



The present part begins with a general account of the group, 

 which follows in the main the lucid model furnished by Oehlert in 

 Fischer's Manuel de Conchyliologie, differing therefrom by the incor- 

 poration of the fresh knowledge acquired during the last seven years. 

 After a synopsis of the habits of the Brachiopoda and of their 

 bathymetric and geographical distribution, the latter illustrated by a 

 detailed map, there follows a full description of the shell with its 

 external and internal markings. A closer attention to the facts of 

 growth has recently led zoologists to distinguish between the various 

 methods in which the passage for the stalk or peduncle has become 

 more or less closed by shelly matter or stereom in different genera of 

 Brachiopoda. Those who wish to learn the meanings of the terms 

 delthyvium, deltidium, dcUidial plates, chilidium, listrium, and syrinx, will 

 here, and here only, find them fully explained. Next to this comes a 

 clear and succinct account of the anatomy of the soft parts of the 

 animal and of those internal skeletal structures connected with the 

 so-called " arms " or lophophore that are of such importance in 

 classification but so hard to investigate and comprehend. We find 

 herein full use made of the recent researches of Joubin, Oehlert, 

 Beecher, and others, of which accounts have from time to time been 

 given in Natural Science, while, in the description of the development, 

 ample notice is taken of the growth of the shell as well as of that of 

 the soft parts, and it is recognised that developmental change does not 

 cease at the close of embryonic life, but continues through the 

 brephic, neanic, and succeeding stages. 



With the way thus cleared for him, the student passes next to the 

 study of all the genera, both recent and fossil, beginning, of course, 

 with the Inarticulate Brachiopods, and then advancing through the 

 Orthoid, Strophomenoid, and Productoid groups of the Articulata. 

 The order that is followed in the descriptions of the genera is 

 precisely the same as that of the larger " Introduction " to which we 

 have already referred. The only differences appear to be the 

 admission of Beecher's Patevina, which for some reason was excluded 



