NATURE 



97 



THURSDAY, JUNE 2, 18S1 



ARCTIC ECHINODERMATA 

 A Memoir on the Echinodermata of the Antic Sea to the 

 IVest of Greenland. By P. Martin Duncan, F.R.S., 

 and VV. Percy Sladen. Pp. 82, Six Plates. (London : 

 Van Voorst, 1881.) 



MESSRS. DUNCAN AND SLADEN will receive 

 the thanks of zoologists for the publication of this 

 memoir, which will owe its importance as much to the 

 care with which it has evidently been prepared, as to the 

 interest of the group with which it deals, and the value 

 that it has in being a monograph of a definite zoological 

 region. The time would, indeed, seem to have come 

 when no further question is possible as to the existence of 

 a characteristic circumpolar fauna ; nearly ten years ago 

 Prof. Alex. Agassiz directed attention to the wide distri- 

 bution of that common form, which has unfortunately so 

 very long a name, the regular Echinid — Strongylocentrotus 

 drobachicnsis, in his " Revision of the Echini," and the 

 researches of Mr. Seebohm have led him to a similar 

 conclusion as to the circumpolar distribution of Birds. 

 Further evidence is given by the present authors, who 

 sum up the matter thus : — 



" When these details are carefully considered, it becomes 

 evident that eachoneof the great groups of Echinodermata 

 tells the same story regarding distribution. The fauna, 

 as a whole, is not an extension northwards of species from 

 more temperate climates, but is essentially circumpolar." 



Where the range is so wide considerable variations are 

 to be expected in the characters of the species, and we 

 feel inchned to attach as much importance to the accounts 

 which the authors give of the variations they have been 

 able to observ-e as to their technical zoological definitions 

 of the species. We have been unable to find in the 

 memoir any notice of the number of specimens which 

 were accessible to the authors, but we believe it was quite 

 large enough to have made the account of varietal forms 

 a necessary part of a complete account. 



It was, at any rate, large enough to make the number 

 of new species very small ; a new Antedon, a new member 

 of Sars' interesting genus Pedicellaster, to which Mr. 

 Sladen has given the appropriate name oi palaocrystallus, 

 make up, with an Ophiurid described by Prof. Duncan, 

 the sum of our gains in that direction. So striking were 

 the characters of this Ophiurid that it was found necessary 

 to form a new genus for its reception ; curiously enough 

 Dr. Duncan proposed a generic term — Luetkcina—vi\{\c):x 

 has already been twice used in zoology ; but this was a 

 matter of slight importance, as Messrs. Koren and 

 Daniellsen had the priority in recognising the generic 

 distinction of the Ophiurid in question, and of giving 

 it the name of Ophiopletira. This priority was how- 

 ever merely a matter of months, and not of years, as the 

 English naturalist would lead us to imagine by leaving 

 uncorrected in his proof the date of 1867 for 1877 (see 

 torn, cit p. 54). Dr. Duncan holds to the view he ex- 

 pressed in 187S that the form has affinities ^\x\\Amphiura 

 and Ophioglypha ; what Prof. Lyman's views are it is 

 impossible to state very definitely, but from the position 

 which he has given to Ophiopleura in his lately- published 

 Vol. XXIV. — No. 605 



"Preliminary List," it would seem that he attaches greater 

 importance to its Ophioglyphan than to its .\mphiuran 

 characters. 



We are not quite sure that we should agree w ith some 

 of Mr. Sladen's views on nomenclature ; but it is, we 

 fear, too late now to raise a protest against the use of the 

 term Asteracanthion ; as the genus to which the name is 

 applied has some eighty constituent species, it would be 

 a matter of satisfaction if of the parties who use Astera- 

 canthion or Asteiias one or other would yield to the argu- 

 ments adduced by the others. We must confess that for 

 ourselves the latter term appears to have every advan- 

 tage both of right and of convenience over the more 

 unwieldy title of Midler and Troschel. It is much more 

 satisfactory to direct attention to the way in which the 

 authors have grappled with an old and unknown synonym 

 in the case of Astrophyton Agassizii. In the year 1819 

 Dr. Leach applied the specific term arcticus to a speci- 

 men of " Corgonocephalns'" brought home by Sir John 

 Ross ; the definition of this species was toD ambiguous 

 and short for practical purposes, and it was not until 

 Stimpson described the Invertebrates of the Grand 

 Manan that the Arctic form got the name by which 

 it has since been called by every naturalist who has 

 had occasion to mention it ; Lyman, Verrill, Ljungman, 

 Liitken and Norman have all known it as Astrophyton 

 Agassizii. The specimen which is supposed to be the 

 type of Leach's description has no title attached to it, or 

 any known history ; in other words, it can never he known 

 what Leach meant to describe, though it is easy enough 

 to gieess ; under these circumstances (by detailing which 

 the authors take, as we hope, the wind out of any mere 

 bibliographer's sails), " we do not feel justified in restoring 

 Dr. Leach's name." 



This is an eminently satisfactory conclusion ; ill-drawn 

 definitions and unlabelled or wrongly-labelled specimens 

 have had their day, and a good long day has it been, in 

 hampering the progress of a growing science ; if zoology 

 is to advance with the other branches of biology, a purist 

 sense of justice must not step in and lead us continually 

 away from the real business of natural history to the 

 dryasdust occupation of elaborating synon)Tnical lists. 

 A dictator-speaker and some rules of urgency might well 

 be invented in the interests of zoological progress. 



The six plates, on which twenty-six of the thirty species 

 described in this volume are carefully figured, make a 

 very useful addition to a work which the Government 

 Grant Fund of the Royal Society were fully justified in 

 subsidising. F. J. B. 



GREEK GEOMETRY 

 Greek Geometry, from Thales to Euclid. Part II. By 

 G. J. Allman, LL.D. Extracted from " Hermathena,"' 

 Vol. iv. No. vii. 49 pp. (Dublin : University Press, 

 iSSi.) 



IN NATURE, vol. xviii. p 291, we briefly referred to the 

 first part of Dr. Allman's work, which gave an account 

 of the earlier geometers, more especially treating of the 

 labours of Thales and Pythagoras. The opening years of 

 the fifth century before the Christian era were very dark 

 ones for Greece, but " then followed the glorious struggle. 

 . . . A solid basis was thus laid for the development of 



