NA JURE 



577 



THURSDAY, OCTOBER i; 



Tiro RECENT VOLUMES ON ARACHNIDA. 

 Oil T2V0 Orders of Arachnida. Opiliones, especially 



the Suborder Cyphophthalmi, and Riciniilei, namely, 



the Family Cryptostemmatoidae. By Dr. H. J. 



Hansen and Dr. W. Sorensen. Pp. 1-182 ; 9 plates. 



(Published by aid of a subsidy from the Royal 



Society of London, Cambridge, 1904.) Price 155. 



net. 

 Palaeozoisclie Aracliiiidcii. By Prof. Dr. .\nton 



Fritsch. Pp. 1-80 ; 5 plates and many text figures. 



(Prag : Selbstverlag. in comm. bei Fr. Rivndc, 



1904.) 



AR.\CHNOLOGISTS must unite in a vote of 

 thanks to Drs. Hansen and SorenseiL for their 

 splendid achievement in producing their treatise on 

 Arachnida. The volume, announced many years ago 

 as in preparation, is based upon a wealth of material 

 borrowed from every available source such as no 

 other taxonomists have been able to examine. It is 

 ;i monument of careful research, and in every way 

 worthy of the high reputation of its authors. Though 

 written in a foreign tongue, the letterpress contains 

 no passage of doubtful meaning; and Hansen's 

 inimitable drawings have received full justice from 

 the lithographic skill of Wilson at Cambridge. The 

 Royal Society was well advised in contributing to the 

 cost of publication. 



The first and most valuable part of the book deals 

 with the Opiliones, a highly specialised order the 

 morphology of which has baffled previous workers. 

 By the comparative and careful study of a host of 

 forms, the Danish authors have succeeded in explain- 

 ing the complicated structure of the genital area, or 

 at all events in offering an e.xplanation which will 

 probably stand unless ultimately disproved by embry- 

 ology. They have accepted the opinions of Simon and 

 Thorell as to the division of the order into three sub- 

 orders, and supplied diagnoses of the families of the 

 Palpatores. In the case of the Cyphophthalmi, the 

 least known of the suborders, a complete monograph 

 of all the species is given, together with some new 

 anatomical details, including the important discovery 

 that the so-called ocular tubercles bear, not eyes, but 

 the orifices of Krohn's glands. Incidentally, Stecker's 

 monster, Gibbocellum, is disposed of, and. It is safe 

 to say, will never again figure in literature. 



The second part deals with an order of peculiar 

 Interest, the Ricinulei or Podogona, which has 

 existed unchanged from Carboniferous to modern 

 times. Amongst the anatomical discoveries made by 

 Hansen and Sorensen, two stand out as of the greatest 

 interest, namely, the presence of a pair of tracheal 

 respiratory organs in the prosoma and of the elements 

 of nine somites in the opisthosoma. The association 

 of this order with the Pedipalpi, ."Vraneje, and Palpi- 

 gradi is of interest, even if the reasons for it are 

 unconvincing; but surely greater prominence should 

 have been given to the fact that Borner anticipated 

 the Danisli authors in this matter ! 

 NO. 1876, VOL. 72] 



Exact and admirable, however, as the work is, it 

 must not be regarded as above criticism ; nor must all 

 the statements be accepted with a childlike faith. 

 Far from it. The limitations of the authors are well 

 known and are sufficiently in evidence in this volume, 

 more especially in the pages dealing with the Micrura. 

 For example, Borner's view that the " labia " in 

 .Arachnida are not homologous sclerites is worth far 

 more than the unreasoned dismissal it receives ; and 

 it is not very obvious why the first abdominal sternal 

 plate in the Ricinulei is homologised with the pre- 

 genital rather than with the genital sternite of the 

 Pedipalpi. Exception also must be taken to the 

 application of the term " antenna " to the appendages 

 of the first pair, and of " mandibles " to the basal 

 segment of those of the second pair, in the Arachnida. 

 The first change is defensible only on the grounds 

 that the chelicerse of the Arachnida are the homo- 

 logues of the antennae of insects and of the antenna 

 of the first pair in crustaceans. Those who adopt 

 this terminology, however, must consistently apply 

 the term " antenna " to the buccal gnathites of Peri- 

 patus. Again, the name " mandible " is presumably 

 given to the basal segment of the appendages of 

 the second pair because of its supposed homological 

 correspondence to the " mandible " of the insects or 

 crustaceans — an opinion not generally accepted. 



Points of this kind, however, would scarcely be 

 worth mentioning were it not for the apparent in- 

 clination on the part of the authors to forget the 

 possibility of two or more views being held on matters 

 about which embryology is, up to the present, silent. 

 As a last word of praise, may we, in all sincerity, 

 congratulate the authors on the considerate tone 

 of their criticisms and on the general absence of 

 that air of self-satisfied arrogance for which certain 

 Danish publications on .Arthropoda have gained an 

 unenviable notoriety? It is to be hoped" that the 

 English supervision of the letterpress is not in any 

 way responsible for this improvement. 



Dr. Fritsch 's monograph of the Paleozoic Arach- 

 nida is a volume of a quite different character. 

 Plainly speaking, it is an anachronism reminiscent 

 of the dark days of palasontology when that science 

 was held to be independent of neontology, or at all 

 events independent in the sense that an acquaintance 

 with the structure of the living species of a group 

 was regarded as superfluous for the correct determin- 

 ation and description of its fossil forms. The com- 

 parative morphology of recent .Arachnida, even with 

 well-preserved material for examination, is difficult 

 enough. Was it likely, then, that any great measure 

 of success would attend the efforts to interpret the 

 elusive structural points of Carboniferous fossils of a 

 palaeontologist unguided by scientific familiarity with 

 recent forms? But, although want of the requisite 

 knowledge is plainly attested and shatters all con- 

 fidence in the alleged observations and attempted 

 restorations, yet without examination of the speci- 

 mens themselves no one has the right to affirm posi- 

 tively that a statement is false or a drawing in- 

 accurate in any given particular. However strongly 



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