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SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 97 



series of dorsoventral lateral muscles (dznn) attached dorsally and 

 ventrally on the body wall. A condition thus arises in the Ony- 

 chophora that has no counterpart in the annelids or arthropods, for 

 in the latter the nerve cords, even when laterally situated, have no 

 barrier to a median approximation or union. 



The major part of the brain, from which arise the antennal and 

 optic nerves, is shown by Sedgwick (1888), Kennel (1888), and 

 Evans (1902) to be generated from the paired ventral organs of 



iva 



AntN 



Fig. 25. — Brain of Peripatoides novae-aealandiae Hutton. 



A, dorsal surface of brain and anterior parts of nerve cords, showing posterior 

 antennal commissure and dorsal position of antennal tracts. B, ventral surface 

 of brain, with remnants of ventral organs. C, lateral view of brain and stomo- 

 daeal connectives. 



AntCom, antennal commissure; AntNv, antennal nerve; AntT, antennal tract; 

 b, motor nerves of antenna ; E, eye ; /, median dorsal nerve ; i, stomodaeal 

 nerves; I Com, first ventral commissure; /, k, nerves of jaw; NC, nerve cord; 

 OpL, optic lobe; StCcm, stomodaeal connective; iVO, remnant of first ventral 

 organ. 



the head (figs. 23 B, 27 B, iVO). Evans says that the brain includes 

 also a pair of anterior "archicerebral lobes" belonging to the apical 

 part of the head, but in his account of the embryonic development 

 of Eoperipatus weldani he makes no mention of observing a separate 

 origin of such lobes, and attributes the entire brain, except a pos- 

 terior part, to the neural elements derived from the cephalic ventral 

 organs. The ventral organs of the head, unlike those of the body, 

 are finally invaginated as vesicles connected with the nerve tissue ; 

 eventually they are reduced, but persist as the small bodies attached 

 to the ventral side of the brain (fig. 25 B, C, iVO). 



