106 MALCOLM LAURIE. 



and Splioerogyna ven tri cos a^ one of the Acarina iu which 

 the young are born sexually mature. 



I may fitly here express my thanks to Professor Ray Lan- 

 kester not only for the suggestion that I should work at this 

 interesting subject^ and for the generous way in which he has 

 provided me with material, but even more for his continual 

 and invaluable assistance and advice while the work has been 

 in progress. 



Historical Introduction. 



Johannes Miiller^ gave a short description, with five or six 

 figures, of the development of Buthus. Owing to its brevity 

 and the absence of any attempt to ascertain the internal 

 arrangement, his paper is of little value except from an histori- 

 cal point of view. 



Duvernoy^ gives also only a few figures of Buthus and 

 of another form, probably Euscorpius. He describes at some 

 length a cord (baguette) which he says passes from the appendix 

 of the follicle in Buthus to the mouth of the embryo, and which 

 Miiller had compared to an umbilical cord. I hope to be able 

 in a future paper to give a detailed account of this and other 

 curious points in the development of Buthus. The chief value 

 of Duvernoy's paper was that he reconciled the contradictory 

 descriptions of the ovary which had been given by Miiller and 

 Rathke.^ While doing this he makes a rather serious mistake 

 in describing the ovum of Buthus as occupying the whole of 

 the diverticulum of the ovarian tube, instead of only a small 

 space at the top. 



The next writer on this subject is Leon Dufour,^ who gives 



• Joh. Miiller, " Beit. z. Anat. des Skorpions," ' Meckel's Arch. f. Anat. 

 u. rhys.,' Bd. xiii, 1828. 



- Duvernoy, " Fragments sur les organes de la generation de divers Ani- 

 maux," 'Mem. de I'Acad. des Sci. de I'lnstitut,' t. xxiii. 



' Ratbke, " Zur Morphologic," ' Reisbemerkungen aus Taurien,' 1837, 

 Riga, 4to. 



■* Dufour, " Hist. Anat. et Pbys. de Scorpions," Mem. Presentes ii I'Acad. 

 des Sciences,' t. xiv, 1856. 



