592 



A. WILLKY. 



I'lG. 4. — A. valdivifc. Diagram of anterior cud from above to 

 sliow tlie relations of tlie rostral cavities. After Goldsclnniiif, 

 somewhat simplified. Rh.l. Lateral rostral cavity proceeding from 

 tiie first myoccel. llh.v. Ventral rostral cavity, vrk. Ventral 

 rostral canal proceeding below the notochord from tlic ventral 

 canalis commiinic-ans {qkv) between the first myotomes, sbrk. Sub- 

 dorsal rostral canal proceeding al)ove the notochord from the dorsal 

 canalis commuuicaus [qhd). drh. Dorsal rostral canal continued 



