574 



NATURE 



{April 23, 1885 



brought up both Rhizocrinus lofotensis and the second 

 species, R. rawsoni, in the West Indian Seas ; while Sir 

 Rawsoo Rawson, Governor of Barbadoes, who had been 

 interested in the work by Dr. Carpenter, obtained three 

 specimens of the singular genus Holopus (previously 

 known as a recent type by only a single specimen so im- 

 perfect that its crinoidal nature was doubted), and several 

 Pentacrini belonging to species which had been previously 

 obtained for Wj-ville Thomson by Mr. Damon's collectors 

 in the same region. 



This was the sum of our knowledge, alike of types and 

 of localities, when the Challenger Expedition set forth in 

 1872. The collections made during her voyage, supple- 

 mented by those made in the West Indian area by the 

 U.S.A. surveying-ship Blake (types of which were placed 

 by Prof. A. Agassiz in the hands of Sir Wyville Thomson 

 for description), and a few gatherings from other sources, 

 now raise the total of existing generic forms to 6, and of 

 species to no less than 32 ; at the same time demon- 

 strating the very wide diffusion of the stalked Crinoids 

 over the oceanic floor, and showing their bathymetric 

 range to extend from depths of less than 100 fathoms to 

 2500. A large collection was also made by the Challenger 

 of unstalked Comatulida, including the singular aberrant 

 genus Actinometraj together with a single specimen 

 (recently described by Dr. P. H. Carpenter 1 under the 

 generic designation Thaumatocrinus) of an unstalked 

 type which presents a most singular survival of Palaeo- 

 crinoidal characters. 



Finding, on his return from the Challenger Expedition 

 in 1876, that Dr. P. Herbert Carpenter had been further 

 prosecuting the study of the Comatulido?, on the basis 

 laid down by his father, Sir Wyville Thomson placed in 

 his hands the whole Challenger collection of unstalked 

 Crinoids, which included not less than 150 new species ; 

 keeping in his own charge the collection of stalked 

 Crinoids (together with the types of the Blake collection), 

 on which he intended himself to report. This intention, 

 however, he did not live to fulfil ; and on his untimely 

 death in March, 1S82, Mr. Murray requested Dr. P. H. 

 Carpenter to undertake the stalked Crinoids also. Beyond 

 naming (mostly without diagnoses) several new genera 

 and species, and directing the execution of 28 plates, Sir 

 Wyville Thomson had made no preparation whatever for 

 his Report ; and on his successor, therefore, almost the 

 whole labour of its production has fallen. The result has 

 fully justified Mr. Murray's selection ; for we feel sun. Ji.it 

 in proportion to the previous knowledge possessed by any 

 student of this Monograph, will be his admiration of the 

 masterly skill with which the knowledge derived from the 

 careful and thorough study of every existing type at 

 present known is made to elucidate the structure and 

 life-history of the extinct Crinoids : this being no less 

 apparent in the case of the Pa , which differ 



most widely from existing forms, than in that of the 

 Neocrinoidea, many of which are represented in our 

 existing fauna by forms that differ from them only speci- 

 fically. In this, his opm magnum, will be recognised that 

 combination of a remarkable aptitude for the appre- 

 hension of details, with a philosophic grasp of his subject 

 as a whole, by which Dr. P. H. Carpenter's previous 

 tributions to its literature have been distingui 



1 Philosophical Transactions, 1883, p. 919, and "Report," p. 370. 



making him equally at home in characterising a specific 

 type, in working out the minutest features of its organisa- 

 tion, and in discussing the homologies of the Crinoidea 

 with those of the other divisions of the great Echinoderm 

 group. Whilst giving the fullest credit to his predecessors 

 and contemporaries, he has endeavoured to determine 

 every point for himself; frequently clearing up an ob- 

 scurity, or satisfactorily settling a disputed question, by 

 more extended research of his own. And where he has 

 found his own inferences from the study of existing types 

 to disagree with those of Palaeontologists who had 

 acquired a deserved reputation for their labours on the 

 fossil Crinoids, he has set forth the grounds of their 

 opinions, and his own reasons for dissenting from them, 

 with impartial fairness. This is conspicuous in his dis- 

 cussion of the morphological relations between the Neo- 

 crinoids and the Palceocrinoids ; as to certain points of 

 which he is at issue with the highest authority upon the 

 latter group, Mr. Charles Wachsmuth, of Burlington, Iowa. 

 U.S., which locality seems its metropolis. " We have 

 approached the subject," he says, " from different sides ; 

 but upon one point we are in complete accordance — viz. 

 the desire to find out the truth." 



The first division of the Report, extending to 185 

 quarto pages, is devoted to the Morphology and Natural 

 History of the Crinoidea generally, treated under the 

 following heads : — (1) The skeleton, with the modes of 

 union of its component joints ; (2) the stem and its 

 appendages ; (3) the calyx ; (4) the rays ; (5) the visceral 

 mass ; (6) the minute anatomy of the disk and arms ; 

 (7) the habits of recent Crinoids, and their parasites ; (8) 

 the geographical and bathymetrical distribution of the 

 Crinoids ; (9) the relation between the recent and the 

 fossil Neocrinoids ; and (10) the relations of the Neo- 

 crinoids to the Palreocrinoids. All these subjects are 

 treated with a completeness which leaves nothing to be 

 desired ; rendering this portion of the work a most admir- 

 able Introduction to the study of the Crinoidea generally, 

 without a thorough mastery of which no one can hence- 

 forth be qualified to discuss any portion of the group. 



The second division commences with a discussion of 

 the principles on which the Classification of the Crinoidea 

 should be based ; after which, every type of Stalked 

 Crinoids at present known is fully described, and its rela- 

 tions discussed. A few of the most interesting additions 

 to our previous knowledge will be briefly noticed as 

 samples of their value. 



The structure of the strangely aberrant Holopus — in 

 which the basal and radial plates are completely anchy- 

 losed into an asymmetrical tube-like calyx, fixed by an 

 irregularly expanded base, while the arms are exception- 

 ally massive— is elucidated as fully as the state of the 

 specimens permitted ; and it is shown that not only the 

 Cretaceous Cyathidium, with the Liassic Cotylecritius and 

 Eudesicrinus, which had been previously referred to the 

 family Holopidce, but also the Upper Silurian Edrio- 

 erinns of Hall, are to be associated with it ; so that the 

 pedigree of this family seems more ancient than that of 

 any other recent type at present known. 



The new genus Hyocrinus, instituted by Wyville 

 Thomson for a beautiful little deep-sea Crinoid bearing a 

 superficial resemblance to Rhizocrinus, is shown by Dr. 

 1'. 11. Carpenter to have distinctive characters of such a 



