104 Miss Agnes Crane — Evolution of the BracHiopoda. 



and palseobiological research. The veteran is Professor James Hall, 

 Director of the Geological Survey of the State of New York, that 

 excellent training-ground for such able palfeoiitologists as Whitfield, 

 AValcott, and Clarke. Beecher and Schuchert, we believe, also studied 

 Brachiopoda at Albany in Hall's private and State collections. It 

 was at Albany that the Memoir on the Development of some Silurian 

 Brachiopoda, bv Dr. C. E. Beecher and Mr. J. M. Clarke (14), was 

 published in 1889. 



The material for this Memoir was derived from a collection 

 weighing seven tons. From this fifty thousand specimens of 

 Brachiopoda were washed out, sifted, selected, and referred to their 

 respective genera and species. The horizon was that of the Niagara 

 shales of the Upper Silurian formation; locality, Waldron, Indiana, 

 U.S.A. All stages of growth of the individuals of a species were 

 thus obtained. Some of these, if found by different observers in 

 various localities at other times, might well have been referred to 

 distinct species, whereas when placed in a line with the smaller and 

 larger examples of their species the relationship becomes at once 

 apparent, and the individuals fall into their place in the natural series. 



From their laboi'ious research the authors, Messrs. Clarke and 

 Beecher, deduced the highly suggestive conclusion that the early 

 stages of species belonging to such distinct groups as Ehynchonella, 

 Spiri/er, Athyris, Nucleospira, and the Meristoids, resemble each 

 other so closely that the genera can then be determined only by 

 comparatively trivial features. 



This Memoir was followed, in 1892, by that remarkable "Intro- 

 duction to the Study of the Palasozoic Brachiopoda," by James Hall 

 and J. M. Clarke (38), which bids fair to become the Bible of 

 the brachiopodist, and to revolutionize the study of the Brachiopoda 

 in general. And it is to Albany that we now look for the completion 

 of those fruitful studies in the generic evolution of this ancient 

 Class.i 



Our knowledge of the larval and later stages of individual growth 

 in the living species is mainly due to the investigations of Fritz 

 Miiller, McCrady, Morse (56, 57), Brooks (12), Beyer (10), Shipley, 

 Schulgin, Kowaleveski, Lacaze-Duthiers (51), Friele (36), Eugeno 

 Deslongchamps (33), Dall, Beecher (4, 5), and Fischer, Daniel and 

 Pauline (Ehlert (59, 60, 61). 



It is, therefore, to Hall and Clarke that we owe the most searching 

 inquiry into the genetic relationships and characteristics of the 

 numberless ancient fossil forms of the class (38), and to Beecher 

 and Clarke (14) important and suggestive studies in individual or 

 ontogenetic development of Silurian species, and to the first-named 

 correlations in ontogeny with phylogeny (8). 



' The main text of part ii. vol. viii. Brachiopoda (Palseontology of New York) 

 has since been issued. The printing of the vohirae of quarto plates is, we regret 

 to learn, still delayed, through no fault of the authors. We have been favoured 

 by Professors Hall and Clarke, since the first part of this paper went to Press in 

 January last, with advance sheets of their ' ' Summary of the Evolution of the Genera 

 of Palaeozoic Brachiopoda," destined to accompany the volume of Plates, and thus 

 to complete their masterly survey of the Brachiopoda. 



