THE ANNALS 



AND 



MAGAZINE OF NATUBAL HISTOEY. 



[FIFTH SERIES.] 

 No. 27. MARCH 1880. 



XVI. — Investigations on the Development of the Spiders. 

 By Dr. J. Barrois *. 



[Plate IX.] 



My researches upon the development of the Spiders have been 

 directed to various species — Tegenaria domestica, several 

 undetermined species of Lycosa, and especial \jEpeira diadema, 

 already studied by Herold. The object that I particularly 

 proposed to myself was to trace by means of sections the 

 arrangement of the lamella} and the phenomena of internal 

 development, which have never been investigated in this 

 group of animals. My studies have led me to modify some of 

 the opinions hitherto accepted upon the external development ; 

 and I shall give these results together with the othei's. My 

 process of research has been the observation either of fresh or 

 slightly heated ova, or of ova coloured by bichromate of potash 

 and osmic acid, hardened by alcohol, and cleared by essential 

 oil of cloves ; by means of the last we succeed much better in 

 seeing the different parts. In making the sections, I employed 

 especially Leyser's microtome, now used almost everywhere in 

 Germany, and which I owe to the kindness of Professor 

 Leuckart, to whom I am glad to have the opportunity of 

 offering my thanks. 



* Translated by W. S. Dallas, F.L.S., from a separate copy, furnished 

 by the author, of the memoir published in the ' Journal de l'Auatomie et 

 de la Physiologie,' tome xiv. pp. 529-547. 



Ann. & Mag. N. Hist. Ser. 5. Vol. v. 14 



