280 Revieics — Hall and Clarke — On the Brachiopoda. 



The type of Cordania is Phcstonides cyclurus, Hall, a form "allied 

 to Proetus in the structure of the pygidium and thorax, to Cyphaspis 

 in the cephalon generally, and to Arethusina in its glabella in 

 pai'ticular." Its occurrence is first noted in the Lower Helderberg 

 of New York, with an upward range through the Hamilton group 

 of strata. 



The bulk of this Report, viz. nearly two-thirds of the text of 

 300 pages, all the 22 plates, and 286 intercalated woodcuts, many of 

 which are original productions, is devoted to "An Introduction to 

 the Study of the Brachiopoda," by James Hall, assisted by John M. 

 Clarke, and dedicated to the use of American students. It forms 

 not only an epitome of vol. viii. part i. of the Palseontology of New 

 York, with a general elementary introduction preceding the clear 

 and concise generic definitions well suited to the comprehension of 

 students in general ; but, in fact, the new handbook combines, so far 

 as it goes, all the best features of the previous more technical and 

 restricted summaries of Davidson, Zittel, and Q^jhlert, plus the great 

 knowledge, experience, and literary facility of Hall and Clarke. 

 Although the "Report" was presented to the Senate of New York 

 January, 1891, it is well up to date, and references to various 

 important observations recorded in 1893 are not lacking. The con- 

 cluding part, dealing with the Spire-bearers, Rhynchonelloids and 

 Terebratuloids, it is stated, will be ready for Press in October, and 

 will not, we trust, meet with any untoward delay in publication. 

 Part I. treats of all the Inarticulata. Paterina included, and of the 

 Articulata from the Orthoids to the Productoids, and affords ample 

 proof of its value to students as an authoritative statement of 

 elementary facts concisely presented and elaborated and explained 

 by excellent illustrations of structural characters. 



It presents all the essential facts of the general history, distribution, 

 shell-structure, and anatomy, with such details of embryological 

 phases as are needed to emphasize the importance of ontogeny in 

 clearing up obscurities in the geological and genealogical history of 

 the class in general and of genera in particular — such a manual, 

 in fact, as could be produced only by an expert palasontologist of 

 great experience like James Hall. We trust further handbooks on 

 other invertebrate groups may be forthcoming from the same source. 



The first part contains a map of the distribution of the recent 

 species and a list, alphabetically arranged, of the localized provincial 

 faunas based on Qllhlert's work of 1876-1880, amplified by later 

 discoveries. We would suggest the addition of a chart of specific 

 bathymetrical limit (the data could be easily derived from the publi- 

 cations of Davidson, CEhlert, Monterosata, and others) ; this, with 

 a table of geological range of genera, would localize all needful 

 information in one handbook. Yerily the students of the Brachiopoda 

 in the twentieth century will have great reason to be grateful to 

 the specialists of the nineteenth who have thus consolidated the 

 results of general researches. 



Systematic classification should be the natural outcome and termi- 

 nation of research, not hard and fast limits outlined at the beginning, 

 within which facts discovered later must be enclosed. As Prof. Huxley 



