170 



ME. R. I. POCOCK ON THE 



[June 17, 



end of the proi^oma ; that for the second somite in the pregenital 

 somite ; that for the thiid in the genital somite ; while those to 



Text-fig. 40. 



Nervous system of the Araneae and of the Pedipalpi of the faniilj' ThelypJionidce. 



A. Nervous system of one of the Thelyplwnida (Mastiffoproctus giffantetos). 

 I-VI. Nerves supplying the six appendages of the prosoma. n.o.ni., nerves to the 



median ej'es ; n.o.L, nerves to the lateral eyes (according to Blanchard) ; 

 cb., cerebi'al or supraojsophageal ganglionic mass giving off the nerves to the 

 eyes and to the appendages of the lirst pair ; s.o., subtcsophageal nervous 

 mass giving off the nerves to the five pairs of postoral appendages (II-VI), 

 also the two principal cords (op.n.) innervating the anterior six metameres 

 of the opisthosoma and the paired mediaii nerve {m.n.) which terminates in a 

 ganglion {g) supplying the muscles of the caudal region ; Ig' , Ig", first and 

 second lung-sacs ; gl.r. right, and gl.h left " acid "-gland ; ts., tergosternal 

 muscles. 



[The median nerve-cord has been pulled aside to the right to show the 

 subjacent nervous cords.] 



B. Nervous system of a Mygalomorphous Spider of the family Aviculariidce (modified 



from Blanchard's figure), to show the similarity between the nerves {op.n.) 

 supplying the opisthosoma and those marked op.n. in the figure of Thely- 

 plionus. 



Lettering as in A. 



