MYRIAPODA 



409 



sacs will form muscles for the most part, but part of the inner walls 

 assumes a mesenchyme character. 



The anlagen of proto- and deutocerebrum arise from cells on the sides 

 of the preoral segment which by active radial division form cup-like 



deui 



Fig. 366. — Platyrhacus amauros. Longitudinal section of the brain. (6sm) 

 ment membrane, {deut) Deutocerebrum. (n/) Nerve fibrillae. {prot) Protocerebrum. 

 {From Pflugf elder.) 



Fig. 367. — Platyrhacus amauros. Longitudinal section of germ band after flexure. 

 {ch) Chorion, {cly) Clypeus. {deut) Deutocerebrum. {ggl 1,4) Ganglion of segments 

 1, 4. {ggl.mx l,mx2) Ganglia of maxillary segments, {md) Mandible, (mes) Mesoderm. 

 {m,esc) Proliferation zone of mesoderm, {mx) Maxillae, {prot) Protocerebrum. {prz) 

 Proliferation zone, {tel) Telson. {From Pflugfelder.) 



structures (Figs. 366, 367, deut, -prot) whose bases later join. Cells 

 adjacent to the deeply infolded basal membrane {hsm) then form the 

 nerve fibrillae (Fig. 366, nf). The cup-like depressions disappear during 



