260 n. I. pococK. 



of the appendicular nerves; IsL, anterior ventral apophysis; m., median pro- 

 cess from tlie floor of the subneural arch. 



Fig. 7. — Dorsal view of entosternite of a young Liphistius, sp. ?, siiow- 

 ing the tliick dorsal apophyses (1/^. to ifff.), the two pairs of supernumerary 

 apophyses («/.• and sa.^), and the absence of anterior ventral aj)opliyses. 



Fig. 8. — Dorsal view of the entosternite of Nephila femoralis, an 

 Arachnoniorphous spider of the family Argiopidre, with the single pair of 

 supernumerary apophyses (•?«.'), and without anterior ventral apophyses, as in 

 Li j)histius. 



Fig. 9. — Lateral view of entosternite of a Thelyphonid (Mastigoproctus 

 giganteus) IsL and 2sL, first and second ventral apophyses ; other lettering 

 as in Fig. 2. 



Fig. 10. — Ventral view of entosternite of Pachylomerus nidulans, a 

 Mygalomorphous spider of the family Ctenizida;, showing the persistence of 

 the first (Isi.) and fourth (4*/.) ventral apophyses, and the disappearance of 

 the second and third. 



Fig. 11. — Lateral view of the same, showing the four dorsal apophyses 

 {Ifff. to iiff.) ; p. m., posterior median crest. 



Fig. 12. — Lateral view of entosternite of Actinopus Wallacei (see 

 Fig. 6), showing the four dorsal (IA7. to ii^.) and four ventral {IsL to 

 4*^.) apophyses, the latter meeting in tiie middle line beneath the nervous 

 mass, leaving lateral spaces for the exit of nerves ; »/., median process from 

 subneural arch. 



Fig. 13. — Ventral view of entosternite of Ephebopus murinus (see 

 Fig. 4), showing the persistence of the four ventral apophyses (IsL to 4s/.), 

 with indications of the fifth (5i7.). 



PLATE 14. 



Fig. 14. — Lateral view of the entosternite of Ephebopus murinus, 

 showing the four dorsal {Ifff. to 4///.) and the four sternal {\,if. to 4*/.) apo- 

 physes. This figure clearly indicates the correspondence l)etween the dorsal 

 and ventral apophyses, which suggests their origin from t ergo-sternal muscles 

 (see PI. 13, figs. 4 and 13). 



Fig. 15. — Ventral view of entosternite of Acanthodon opifex, a 

 Mygalomorphous spider of the sub-family Idiopina;, showing the |)crsistence 

 of the first, second, and third pairs of apophyses (Is/, to 'is/.), those of the 

 fourth pair (4s/.) being rudimentary. 



Fig. 10. — Lateral view of tiie same, showing the dnplieation of the third 

 and fourth dorsal apophyses, and the absence of the fourth ventral apophysis. 



Fig. 17. — Mygalomorphous spider of tiie genus Aty pus, dissected from the 



