2 2 o WEB-SPIDERS. 



exception that it is spread over Africa south of the Sahara, extending from 

 Senegambia and Abyssinia southwards into Cape Colony ; but there are no species 

 from Madagascar. It also seems to extend in India farther to the west than do 

 the Thelyphonidce, since species occur at Bombay, and thence spread along the south 

 coast of Arabia from Muscat to Aden. In the Indian region the species are not so 

 numerous as the true whip-scorpions, and in the Philippines they seem confined to 

 caves, living permanently in the dark. None are known from Japan or China ; but 

 in America a few have been recorded from Texas and California, and many from 

 Central America, the West Indies, and South America, as far down as Patagonia. 

 Like the last, this group dates back to the Carboniferous, a single genus, 

 Grcwphonus, having been described from the coal-measures of North America. 

 A single specimen has also been discovered in the Miocene gypsum beds of Aix. 

 The existing forms may be all included in the family Tarantulidce ; the genera 

 being mainly characterised by the degree of development of the horny pieces on 

 the lower surface of the cephalothorax. In habits the group resembles the last, 

 except that the species, instead of digging burrows, avail themselves of natural 

 crevices and holes, hiding beneath stones or fallen tree trunks, for which they are 

 adapted by the flatness of their bodies. The species frequenting grottoes in the 

 Philippines cling to the walls, with legs extended, and dart into rocky fissures at 

 the least disturbance. 



Order Palpigradi. 



This group is represented only by a single South European form (Koenenia 

 mirabilis). Structurally, this minute creature occupies a position intermediate 

 between the whip-scorpions and the Sol if u gee. As in the Thelyphonidce, there is 

 a long, jointed tail, articulated to the last abdominal segment, which, with the two 

 that precede it, is narrowed to form a movable stalk ; but, as in the Solifugos, 

 the abdomen consists of only ten segments. The carapace is segmented and has 

 no eyes ; but in the structure of its appendages Koenenia is peculiar. The 

 mandibles are large, pincer-like, and composed of three segments, but the palpi and 

 all the legs are alike, being long, slender, and composed of a number of segments. 

 The legs of the first pair, however, are the longest, as in the Pedipalpi. 



The True or Web-Spiders, — Order Arane^e. 



In many points of their organisation, the true spiders approach the tailless 

 Pedipalpi. They have, for instance, a deep waist, separating the cephalothorax 

 and the abdomen ; the limbs are arranged radially round the cephalothorax, which 

 is covered below by a single sternal plate, to which a labial piece is united in front, 

 and above by a carapace bearing, in the majority of cases, eight eyes. Moreover, 

 in some instances, there are four pairs of lung-sacs, as in the Pedipalpi, although 

 generally the hinder pair are replaced by tracheal tubes. The differences between 

 the two orders are, however, striking enough. Thus the four pairs of legs are 

 alike, being composed of seven segments, and used for locomotion ; while there are 

 no great seizing limbs, the appendages of the second pair being short and leg-like, 

 though composed of but six segments ; of these the basal is termed the "maxilla, on 



