368 ABiOKNIDA. 



the young are born jrvruments either for attack or defence. The repre- 

 as furnishing K'labium of an insect, in the Arachnidans, has no palpi 



(95Q V with it. 



iii>^o56.) In Spiders, the organization of the mouth is altogether dif- 

 ferent. The mandibles (fig. 186, o o) are each terminated with a 

 moveable fang (c), which ends in a sharp point, and is perforated near 

 its extremity by a minute orifice, from which, when the Spider bites, a 

 venomous fluid of great potency is instilled into the wound inflicted ; 

 such, indeed, is the malignity of this poisonous secretion that its effects 

 in destroying the life of a wounded insect are almost instantaneous, and 

 in some of the large American species even small birds fall victims to its 

 virulence. The organ in which the poison is elaborated is represented 

 in the figure above referred to ; it is a long and slender bag, from which 

 an attenuated duct may be traced through the body of the mandible as 

 far as the perforated extremity of the fang. 



(957.) The palpi connected with the maxillaa of the Spider are termi- 

 nated in the female by a simple hook ; but in the males of many species 

 they exhibit a conformation slightly resembling the forceps of the Scorpion, 

 although provided for a very different purpose. When closed (fig. 185, B), 

 the terminal part of the palpus presents a club-like dilatation, which, 

 however, on close inspection will be found to consist of several pieces 

 (fig. 185, A, a, b, c, d, e), connected with each other by articulations, and 

 capable of being opened out in the 



manner represented in the figure. Fi &- 185> 



This strange instrument was for- 

 merly imagined to be the penis of 

 the male Spider, and was thought 

 to contain the terminations of the 

 seminal ducts : this supposition, 

 however, has been proved to be 

 erroneous ; for the palpus is im- . . 



, .. Palpus of male Spider. 



perforate, and the sexual apertures 



of the male are situated elsewhere ; but the organ in question is never- 

 theless apparently used in the process of impregnation, in a manner to 

 be explained hereafter. 



(958.) Both in Scorpions and Spiders the alimentary canal is exceed- 

 ingly narrow, presenting scarcely any of those dilatations met with in 

 the digestive organs of insects. This is a natural consequence of the 

 nature of their food ; for as they live entirely upon animal juices 

 sucked from the bodies of their victims, there could be little necessity for 

 the presence of capacious receptacles for nutritious matter, or for any 

 reservoirs for the accumulation of effete material. 



(959.) In the Scorpionidae there is no stomachal dilatation whatever : 

 a straight intestine passes directly from the mouth to the anus, situated 

 at the extremity of the abdom n ; and the insertion of the biliary 



