348 Bibliographical Notices. 



former, the main trunks affect a bilateral position, those of the 

 latter are dorso-abdomiual ; that, with one doubtful exception, 

 the blood system is closed, while the tracheal system always 

 (that of a few aquatic larvae excepted) communicates by means 

 of spiracles with the external atmosphere. 



7. That the tracheal and blood systems of Insects come into 

 conjunction only at the peripheric segments, — the main trunks 

 of each observing separate courses. 



8. That the periphery of the circulating fluid system of In- 

 sects is constructed in exact conformity with the Crustacean 

 model, the blood flowing in imparietal channels, in and through 

 which the capillary trachese are conducted, floating in the nutri- 

 tive fluid. 



I remain. Gentlemen, 



Your obedient Servant, 



Thomas Williams, M.D. 



BIBLIOGRAPHICAL NOTICES. 



Insecta Maderensia ; being an Account of the Insects of the Islands 

 of the Madeiran Group. By T. Vernon Wollaston, M.A., 

 F.L.S. London: 4to, pp. 634, plates 13. 



Some persons are singularly qualified for producing a work on the 

 natural history of a country. To give one instance : — Otho Fabricius, 

 a Danish clergyman, spent some years of his life in Greenland, and 

 thus acquired an intimate knowledge of that Arctic land, which 

 modern discovery begins to show must be an immense archipelago 

 bound by one great band of ice. When he left Denmark, with but 

 little knowledge of natural science, but ardently desirous of stu- 

 dving the works of Him, whose word " ut Missionarius ordinatus, 

 ab honoratissimo CoUegio de cursu Evangelii promovendo," it was 

 his calling to proclaim, Fabricius took with him, in 1 768, that na- 

 tural-history cyclopaedia of the time, the ' Systema Naturae' of Lin- 

 naeus, and, urged by those who ordained him, to study Arctic natural 

 history at bis leisure hours, he returned in six years with great 

 materials for a Physical, Geographical and Historical History of 

 Greenland. In May 1779 he wrote the preface of a portion of this 

 work, tlie ' Fauna Groenlandica,' which was accordingly published 

 next vear, and the character of which may be best given in the words 

 of Cuvier : " Ouvrage pre'cieux par I'extreme exactitude des descrip- 

 tions." It is the work of a diligent, observing man, limited by 

 climate to a highly interesting, but comparatively narrow, field. He 

 has but few books to distract him, and but few bibliographical re- 

 searches to make. 



Mr. Wollaston, though he went to a tropical climate, was 

 singularly happy in having such an atmosphere as envelopes an 

 ocean-girt island of limited size, 250 miles distant from a continent 



