May 17, 1906J 



NA TURE 



51 



derm. Some of these become differentiated ililo 

 cpithelio-muscle elements thnt constitute the vaso- 

 thelium, and others into blood-cclls. Thus the study 

 of annelids leads Vejdowsky to conclude that their 

 h;enioccel is a hypoblastic structure sui generis, not 

 riimparable to that of arthropods or of molluscs, 

 but rather to the cardiac vasothelium in vertebrates. 

 •Such a result emphasises that relation of vascular 

 system to the alimentary tract which topography has 

 insisted upon. 



In his article on the morphology of the cestode 

 body, Prof. Spengel stoutly supports the monozoic 

 theory. He regards the Bothriocephalidx as the most 

 primitive tapeworms, and considers that in the highly 

 niodilied Taeniidse we have simply a coincidence of 

 somatic and gonidial segmentation areas. Inci- 

 dentally he suggests the comparison of the scolex 

 with the hinder end of segmented worm, and 

 emphasises the singular nature of the cestodes by 

 pointing out their entire lack of true regenerative 

 power. 



The remaining anatomical papers deal with the 

 modifications of clasping organs in arboreal 

 mammals, with the head of ^collembolous and culicid 

 insects, the nervous system of leeches, and certain 

 abnormal gasteropods. 



Of the embryological memoirs, the accurate and 

 laborious research of Wierzejski on the cell-lineage 

 of Physa will be welcomed as a topographical paper 

 of the first rank. Prof. Mcintosh contributes a well 

 illustrated account of the life-history of the shanny, 

 and then follow memoirs on the early development 

 of the blind-worm, on the breeding habits of Rhino- 

 derma and of the salamanders. 



The physiological papers are of more general 

 interest. Prof. Hacker continues his illuminating 

 work on the skeleton of the Radiolaria by treating the 

 Tripylaria from the same ecological standpoint which 

 he adopted in his paper of last year. Hacker is the 

 most active of a band of workers who are putting 

 new life and new significance into the merely geome- 

 tric descriptions of earlier students of these skeletal 

 products. Dr. Rhumbler gives a further instalment 

 of his work on the mechanics of streaming movement 

 in .Vmccbae, and shows some interesting stream 

 figures produced by dropping chloroform water upon 

 shellac. He fully recognises the inward and auto- 

 genous control that dominates those displays in 

 organisms that we cannot parallel in not-living 

 matter, but he holds that in Amoeba the phenomena 

 of movement and feeding are capable of mechanical 

 explanation in terms of the aggregation theory which 

 he has formulated elsewhere. 



Dr. Jordan contributes an essay on the origin of 

 species in Lepidoptera. His main thesis is to the 

 effect that geographical subspecies, and no other 

 variations, are the material out of which new species 

 have been evolved. Much of the paper is summarised 

 from his earlier work, and represents a line of re- 

 search to which several naturalists are applying them- 

 selves. The work of Petersen on the Fritillaries in 

 particular pursues the method employed by Dr. 

 Jordan, but in a more comprehensive manner, and it 

 NO. 1907, VOL. 74] 



is to be hoped that these important results may bo 

 rendered more available to the student of evolution 

 than they now are by a new mode of presentation, 

 graphic, tabular, or other than textual description. 



Lastly, the memoir of the Baroness von Linden on 

 the influence of heat, cold, and gases upon the color- 

 ation of Vanessid butterflies constitutes a further 

 instalment of the author's prolonged investigation. 

 The general conclusion drawn from these experiments 

 is that whatever lowers the rate of pupal metabolism 

 increases amount of black imaginal pigment and 

 diminishes the extent of red colour in the butterfly. 



F. W. Gambli-. 



THE BIRDS OF TUNISIA. 

 The Birds of Tunisia. Being a history of the birds 

 found in the Regency of Tunis. By J. I. S. 

 Whitaker. 2 vols. Royal 8vo. Pp. xxxii + 294 

 and xviii-l-410. Plates and maps. (London : R. H. 

 Porter, 1905.) Price ;^3 3.5. net. 



THE two handsome and beautifully illustrated 

 volumes containing the history of the birds of 

 the Regency of Tunis form a fitting crown to the 

 years of work in the field, the museum, and the 

 library which their author has devoted to the ornitho- 

 logy of this until recently little known country. They 

 form too a valuable contribution to the avifauna of 

 the western Mediterranean region ; for although the 

 present work purports to be merely a history of the 

 birds noticed in Tunisia, and of their lives as observed 

 in that countrv, the author has thought it advisable, 

 when possible, to allude to the occurrence of the 

 various species also in Algeria and Morocco, as like- 

 wise, in some cases, in Tripoli, and in the Mediter- 

 ranean basin generally. 



The articles on various v^'arblers (especially the 

 interesting remarks on their life-history), and other 

 birds which are met with most commonly in that 

 region, will be most welcome, even to those whose 

 interests are restricted to the birds which figure on the 

 British list. Tunisia, a long and somewhat narrow 

 countr}', stretching from the Mediterranean back in 

 the vagueness of the great desert, presents a great 

 varietv of natural features and climate ; and the con- 

 trast between the well-watered, wooded and moun- 

 tainous region north of the Atlas Mountains and the 

 rainless, sandy and rocky desert country is very great. 

 To these circumstances, and to the fact, pointed out 

 bv the author, that few countries are geographically 

 so favourably situated as the Regency for the observ- 

 ation of the migration of birds, the wealth of the 

 Tunisian avifauna is due. No less than 365 species 

 and subspecies of birds are included in this work ; 

 and only about thirty-five of these have to be relegated 

 to the roll of occasional and accidental visitors. Two 

 beautiful photogravures give an excellent and most 

 truthful idea of the character of the scenery and the 

 traveller's mode of life in the south of the country ; 

 while other plates introduce the reader to some of 

 those wonderful Roman ruins, so marvellously pre- 

 served in that dry, clear air, which so startle the inex- 

 perienced wanderer in the central parts of Tunisia. 



