Mr. T. II. Savory on the Sju'ler Liphistius. 4-i7 



ViMitrally the first ami second .se<Tnieiit3 of the abdomen 

 are provided with phitea, which cover the aperturas of the 

 reproductive system and of the twp pairs of lunt^-books. 

 'IMiH possession o£ two pairs of lung-books and no spiracuhir 

 trachei« is also a primilive feature, shared by Liphistius and 

 the TheraphosK. 



The shape of the abdomen of Li/>histiiis is almost spherical, 

 and this is certainly not a primitive form. la all livinij 



Fig. 2. 



4fe 



Ventral surface. 



s))iders of generalized type the prevailing form of abdomen is 

 elongate or cylindrical, while the spherical form is charac- 

 teristic of the J'^peiridfe, mak'Ts of the elaborate spiral webs, 

 and the Linyphiida^, famons for the bewildering complexity 

 of their genera, distinguishable only by minutiie of structure. 

 Abdomiiuil sphericity may be due to decrease in length or to 

 a development of the diverticula of the intestine, and in either 

 case it is a character in which Liphistiim shows a specializa- 

 tion of its own and a departure from the piimitive tvpe. 



