STUDIES ON THE ARACHNID ENTOSTERNITE. 233 



The entosternite of the Amblypygi is very different from 

 that o£ the Urotricha. The pharyngeal notch is semi- 

 circular and the anterior cornna large. Each bears a pair 

 of dorsally directed apophyses near the apex, also one on the 

 underside, which dips down beneath the pharynx, and one 

 above, at the base, which projects upwards and inwards. 

 The body of the plate itself is wide, narrowed posteriorly, and 

 solid, i. e. without foramina. Near its lateral border on each 

 side arise four apophyses which extend upwards and outwards 

 to be inserted by means of muscular bundles to the under sui'- 

 face of the carapace. The first is very slender; the second 

 and third are approximated at the base ; the fourth is the 

 stoutest. These four spring froui a common ridge beneath 

 which the edge of the entosternite runs out externally into a 

 short angular ci-est to contribute support to the great 

 appendicular muscles (PI. 13, fig. 3). 



It would be unfair to criticise the figure of the entosternite 

 of " Phr3nius " given by Bernard (3), because " the prepara- 

 tion was accidentally destroyed before the drawing was 

 completed." Four pairs of dorsal apophyses are represented, 

 but I cannot satisfactorily homologise them with the six 

 pairs shown in the figure here published (PI. 13, fig. 3). It is 

 stated, moreover (op. cit., p. 20), that this plate lias "only 

 one attachment to the ventral surface, and that is to the 

 intersegmental membrane between the second and third pairs 

 of limbs corresponding with the first pair of apodemes 

 forming the entosternite in Mygale." It is true tiiat there 

 is only one pair of ventral processes, and that they represent 

 the similarly situated processes in Mygale. They are not 

 attached, however^ in the position Bernard states, but to the 

 coxa of the second appendage, the point of their insertion 

 appearing as a horny subcii-cnlar patch on the soft membrane 

 below the mouth, when these appendages are pulled apart 

 and examined from the front. 



4. The Entosternite in the Aranete. 

 lu typical members of the Araneae the entosternite closely 



