876 EXTRACTS FROM FOREIGN PERIODICALS. 



confined to the valueless rules of general classification, by turns wavering, in- 

 complete or false, once rational and philosophic, Helminthology is in more imme- 

 diate need of new researches and guides than any other branch of Natural His- 

 tory. — Annates des Sciences Naturelles. 



3. On a peculiar Human Race of the Atlas. — M. Guyon, principal 

 surgeon to the African army, in a letter to M. Dureau, announces, that there 

 exists at Bougie a native of the interior, a female, supposed to be descended 

 from a white tribe of the Auref mountains. This woman is about 26 or 28 years 

 of age ; has a most agreeable countenance, blue eyes, flaxen hair, beautiful teeth, 

 and extremely fine white skin. She is married to the Iman of the Mahometans, 

 Sidi Hamed, by whom she has three children who bear a considerable resem- 

 blance to him. M. Aeago adds, that this is not so rare an occurrence as may at 

 first be imagined. While going, towards the close of 1808, from Bougie to Al- 

 giers by land, he saw, in the greater part of the villages of the Kabyles, women 

 of all ages who were remarkably white, and who had blue eyes and fair hair. 

 Circumstances prevented him from ascertaining their origin. — Bibliotheque Uni- 

 versale de Geneve. 



4. Formation of Spiders' Webs. — We now continue our abstract of M. 

 Duges' paper " Sur les Araneides," in the Annates des Sciences Naturelles, for 

 September and October, 1836. 



The seventh article treats of the secretion of the web. This secretion takes 

 place in a glandular mass situated at the posterior part of the abdomen ; it is a 

 viscous substance, which dries more or less rapidly according to the species, and 

 according to the fineness of the thread. This substance is insoluble in Avater, and 

 rain breaks the webs without dissolving them. M. Duges thinks, contrary to 

 the opinion of Lister and Latreille — who believe that the threads are forced 

 out — that they are simply drawn out by the motion of the body or of the legs. 



This web first serves to construct habitations varying considerably in different 

 species. Sometimes the threads alone are employed, sometimes mixed with 

 other materials. Some species construct tubes, often very solid ; lastly, we know 

 the singular lids with which the Mygales (Mygale) protect their dwelling. This 

 web serves, in the second place, as every one knows, to form snares for furnishing 

 the food of the Spider. The position of these snares depends on the habits of 

 each species. One of the most important points which M. Duges has studied in 

 this respect, is the means employed by the Epeiras (Epeira) to carry their webs 

 to considerable heights, for which purpose they throw into the air long threads, 

 which are often attached to points very distant from each other. The author 

 has seen, at the extremities of branches, little Spiders, sometimes motionless, 

 sometimes rapidly moving their anterior legs. He succeeded in seeing them 

 draw from their web-former (fdiere), and cause to float freely in the air a bundle 



