136 



COMPARATIVE ANATOMY 



CHAP. 



side, and this ganglion becomes the infraintestinal ganglion. The 

 pleurovisceral connectives, in which these ganglia lie, now cross and 

 give rise to the condition called chiastoneury. The visceral 



uvct 



FIGS. 113, 114, 115, 116. Diagrams to illustrate the shifting forward of the pallial complex 

 along the right side of the body and the development of chiastoneury. p, Mouth ; ulc, ulpl, 

 ulp, original left cerebral-, pletiral-, and pedal-ganglion ; ulpa, urpa, original left and original right 

 parietal ganglion ; ula, original left auricle ; M.OS, uros, original left and original right osphradium ; 

 ulct, urct, original left and original right ctenidiuni ; mb, base of the mantle ; mr, edge of the same ; 

 m, mantle cavity ; v, visceral ganglion ; ve, ventricle ; a, anus. 



ganglion in which these connectives terminate posteriorly lies as 

 before under the intestine. 



It is unnecessary to show in detail how this displacement also affects 

 the heart and its auricles, the osphradia, and the nephridial apertures. 



