Echinological Notes. 
By 
Dr. Th. Mortensen. 
V. The Phylogeny of the Echini. A critical essay. 
Professor R. T. I ackson, the author of the "Phylogeny of 
the Echini”, has expressed the desire of seeing his work") reviewed 
by me. With pleasure I take the task upon me. Though the 
echinological literature has, especially in recent times, received many 
very important contributions, this work represents a rather unique 
enrichment of this branch of science, equally remarkable through 
its magnificent appearance and its high scientific value. To review 
Such a monumental work is in itself both a. pleasure and a honour. 
Meantime Prof. H. L. Clark has published in "Science”, 
June 28. 1912, an elaborate review in which he gives a rather 
detailed summary of the contents and the more prominent results 
of the work. I must join Professor Clark sincerely in his deep 
appreciation of the work and in his admiration for the eminent 
skill and unsurpassed industry and perseverance of the author; but 
the appearance of his review makes it superfluous for me to give 
likewise a summary of the contents of the work, which could not 
avoid being essentially a repetition of what H. L. Clark has already 
Said. Probably also Prof. Jackson will prefer, instead of receiving 
another eulogy in similar terms from my hand, to have a criticism 
1) Robert Tracy Jackson: Phylogeny of the Echini, with a Revision 
of Palæozoic species. Mem. Boston Soc. Nat. Hist. Vol. 7, 1912. 
(With 76 Plates). ' 
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