ARACHNIDS. 



565 



bund a small papilla, which may be considered as the rudiment of 

 a penis. Also in some Acarina a short penis is present. In Pha- 

 'angium, on the other hand, there is a long horny penis which can 

 be extended from the body at the same part as the ovipositor in 

 ;he female, and through which the ductus ejaculatorius extends ; 

 it the upper extremity of the glans is a small hooklet. In the 

 spiders the two efferent vessels, arising from the blind tubes that 

 secrete the seed, run towards the base of the abdomen, where they 

 >pen, without any copulative organ, between the gills. The organ 

 f copulation lies very distant from this opening. In the spiders, 

 tamely, the last joint of the feeler is excavated like a spoon, with 

 various appendages in addition, different in different species, and a 

 iorny, curved filament connected, which lies concealed in the exca- 

 vation, and can be extruded from it. With this club of fat palpi, 

 ;he male, at the time of pairing, touches the sexual parts of the 

 emale, having previously moistened it with a drop of seminal fluid 

 rom the opening of the vasa deferentia. This is thus the copula- 

 ion itself, and by no means, as TREVIRANUS supposed, a prelimi- 

 lary sport to excite the sexual passion : this is the copulation itself, 

 vhich LISTER, DE GEER, LYONET, and others, described so fully 

 jid so interestingly 1 . The danger of being cruelly put to death by 

 he female spider causes the male to make his approaches to her 

 vith anxious caution, and after the congress to betake himself 

 apidly to flight. 



In the development of the arachnids from the egg, after the 

 erminal vesicle has disappeared, there appear to occur, as in many 

 ther animals, clefts and grooves in the yolk-mass. The ger- 

 linal membrane or disc grows slowly round the yolk, closing 

 nally on the dorsal surface. Before this closure is completed, 

 e commencement of the embryo appears on the ventral surface of 

 he yolk. Here are seen, at least in the embryo of the scorpions 

 ccording to the observations of EATHKE, different thickenings 

 ing in pairs near each other in a row, which are the beginnings 

 the segments of the body. From the mucous layer of the ger- 

 linal membrane arises the intestinal canal, which at first is not 



1 See, for instance, LYONET in his translation of LESSER Theol. der Ins. I. p. 184, 

 id in his Reckerchcs, pp. 73 75, and WALCKENAEB Hist. nat. dcs Arancides, v. 8, 

 2cting Theridion beniynum. See also OWEN Lectures on comp. Anat. of invert. 

 \iiim. p. 264, 2nd ed. p. 462. 



