June 14, 1906] 



NA TURE 



153 



of Ihe two races in the treatment of ornament differed 

 so widely that in some pages of the " Book of 

 Kells," for example, the two can be separated as 

 easily as if they were of different colours. It is odd 

 to find that Mr. Kermode describes the interesting- 

 crucifixion shown on p. 72 and here reproduced as 

 "an example of pure Byzantine art." To our eyes 

 it is nearly pure Celtic, and has no relation, artistic- 

 ally, to any Byzantine crucifixion we have ever seen. 

 The statements, however, throughout the '" Notes " 

 are in general accurate and restrained, and there is 

 an entire absence of the wild local enthusiasm so often 

 found in books of this particular character. The 

 " Notes " may be commended as likely to be of groat 

 use to anyone visiting the isl:uid or studying its 

 antiquities. 



yiOLLVSCAN MORPHULOGY.' 



'T^HIS fifth volume of the important "Treatise," 

 -'■ edited by Prof. Ray Lankester, deals with the 

 Mollusca, and is the work of the one biologist capable 

 of doing this group most justice, namely, Dr. Paul 

 Pelseneer. Like its predecessors in the series it treats 

 of the subject almost exclusively from the morpholo- 

 gical standpoint, just such a sufficiency of systematic 

 matter being added as to justify the title, while it is, 

 of course, very far from being, and indeed does not 

 pretend to be, a manual on the phylum. 



Some delay has occurred in its appearance, owing 

 to the need of translation and revision for the press, 

 which has been carried out by Dr. Gilbert Bourne. 



The work itself is 

 an expansion of Dr. 

 Pelseneer's similar 

 contribution to Blan- 

 chard's " Traite de 

 Zoologie. " The 

 Fig. ^.—stfiioj;rra luamiiiata, left side translation is remark- 



S ':;;^Xo''"F7o°^'"ATL°il- ^Wy weU done, and 

 on Zoology.". save in some of the 



opening sentences it 

 is hard to realise that it was not written in English. 

 Not but that there are small slips such as " biannual " 

 for " biennial." The revision, we suspect, has largely 

 consisted in the importation of new terms, so dearly 

 beloved of a certain school of biologists, that do not 

 altogether make for clearness, and are foreign to the 

 lucid style customary in the author's other writings. 

 The opening paragraph on the " general description 

 and external characters " of the Mollusca (p. 3) is a 

 case in point. While the statement (p. 20), " It has 

 been shown that in the Cephalopoda hyperpolygyny is 

 the rule, and in certain .^tlantse and American 

 Unionidoe, hyperpolyandry," inspires the not hyper- 

 critical comment that, without hyperbole, it is hyper- 

 technical. Certainly a glossary will be indispensable 

 to the work. 



One is glad to observe that that mythical monster, 

 the " .Archi-" or " Schematic Mollusc " has dwindled 

 to a shadow of its former self, and now survives solely 

 in a diagrammatic figure as a " scheme of a primitive 

 mollusc " (Fig. ig). For, as Verril pointed out in 

 1S96 {Amer. Journ. Sci., series iv., vol. ii., pp. gi-92), 

 the primitive mollusc is rather to be sought in the 

 early larval stages, such as the Veliger form. Even 

 now one is tempted to think that the " primitive " has 

 been introduced by the translator, since the author in 

 his previous work, to which reference has already been 



I -A Treatise on Zoologv.'" Edited by Dr. E, Ray Lankester, F.R.S. 

 Part V , Mollusca. by Dr. Paul Pelseneer. Pp. ^05 : 301 text illustrations. 

 (London : A. and C. Black, 1906.) Price 15,5. net. 



made, simply labels his figure " Scheme d'un 

 MoUusque," which is rather a different thing. 



Dr. Pelseneer's explanation of the torsion of the 

 gastropod body evidently now meets with Prof. Lan- 

 kester's approval, for it is the only one advanced and 

 is reinforced by an additional diagram. 



A good deal more attention is paid, and rightly, to 

 the shell than in the author's previous writings, and 

 it is interesting to see Sharp's theory of the progressive 

 disappearance of the anterior adductor muscle in 

 certain successive forms of Lamcllibranchs (which was 

 first illustrated by specimens in the Index Hall of the 

 Natural History Museum) made the subject of illu.s- 

 tration, though'in the text this disappearance is made 

 the cause, instead of the consequence, of the alteration 

 of the body-axis. 



One or two other points need further attention. 

 .'Vllusion might advantageously have been made to the 

 origination of the gill in Cyclas, Teredo, and Scio- 

 beretia by perforation of a continuous inembrane : also 

 to the discovery by Dall that Philobrya passes through 

 a glochidium 

 stage, which is 

 therefore not 

 confined to the 

 Unionidae. 



The systematic 

 portion is open 

 to much criti- 

 cism. It does 

 not differ materi- 

 ally from that 

 given in Dr. Pel- 

 seneer's previous 

 works, though 

 there is, so to 

 speak, some 

 shuffling of the 

 cards. It is a 

 great pity, how- 

 ever, that the no- 

 menclature has 

 not been brought 

 up-to-date. This 

 would have pre- 

 vented such an 

 error as record- 

 ing Zonites as 

 British. 



The majority 

 of the illustra- 

 tions, which are 

 all clear and well 

 printed, are dia- 

 grammatic, or elucidate structural features, while 

 of the few pictorial ones most are those used 

 by Owen, without acknowledgment of their 

 source, in his article on Mollusca in the eighth 

 edition of the Encyclopcedia Britannica. The 

 greater number of these are now, very properly, 

 attributed to their rightful authors, but of those still 

 labelled " From Lankester after Owen " it has 

 escaped observation that Nos. 71, 134, and 136 are 

 after Adams, No. 15S after Philippi, and Nos. 66 and 

 135 are from S. P. Woodward's " Manual," while the 

 well-known figure of Sepia officinalis (No. 299) is from 

 Ferussac and D'Orbigny's " Histoire." 



The index would have been more useful had refer- 

 ences to the genera cited elsewhere than in the syste- 

 matic parts been included. 



All these are, however, minor points, and the fact 

 remains that malacologists now possess one of the 

 best-written treatises yet produced in the English 

 langruag-e on the morphology of the Mollusca. 



(B V)^ 



IG. ■2.—Nmitilii<: }}iac7-omphalus creeping on a 

 horizontal surface, anterior view. a, o, t, 

 anterior ophthalmic tentacle; c, eye ; ho, hood ; 

 in, infundibulmn ; /«, nuchal part of the 

 mantle; /*, <', /", posterior ophthalmic tentacle; 

 sh, i^hell. (After Willey.) From " A Treatise 

 on Zoologi'." 



NO. 191 I, VOL. 74] 



