STUDIKS O.V THK AKACHNID KNTOSTEIJNITK. 231 



of the entosternite. Bernard also homologises tlie anterior 

 bars of the scorpion's entosternite with the second pair of 

 ventral apophyses which are affixed to the sternum opposite 

 the base of the third prosomatic appenda^-e (first walking- 

 leg) in the spiders. Since, however, these bars in the 

 scorpion give attachment diagonally to great muscles wliich 

 supply the second and tliird appendages (chela and first leg), 

 it seems far more likely that they represent the anterior bars 

 of the entosternite of the spiders, Thelyphonus, etc., which 

 are similarly continuous with the muscles supplying these 

 appendages (PI. 14, fig. 20). 



3. The Entosternite of the Pedipalpi (Thelypho- 

 nidoe, Phrynida^). 



In the Pedipalpi two types of entosternite are found, one 

 characteristic of the Urotricha (Thelyphonidffi), the other of 

 the Amblyp3^gi (Phrynida^). In the Thelyphonidre tlie main 

 portion of the plate is longitudinally oblong in shape. It is 

 perforated mesially by two foramina, an anterior lai-ge and 

 oval, and a posterior relatively small and circular. The two 

 are separated by a transverse bridge ; a similar bridge 

 separates the anterior foramen from the pharyngeal notch. 

 Near the edges of the upper surface of the right and left 

 bars forming the external framework of the pharyngeal 

 notch and of the foramina, rise five pairs of tendinous pro- 

 cesses which are affixed by muscular fibres to the underside 

 of the carapace. The first rises at the extremity of the 

 anterior cornu, the second just in front of the anterior 

 bridge. The latter apophysis is bifid and projects inwards, 

 backwards, and upwards towards the central depression of 

 the carapace. The others take a more lateral direction. The 

 third rises close to the second and a little behind the 

 anterior bridge ; the fourth just behind the middle of the 

 large foramen ; the fifth on a level with the smaller foramen. 

 Below the latter ma^'^ be seen a bifid tendinous crest running 

 downwards and outwards. Behind this point the entosternite 



