270 



ARTHUR WILLEY. 



total height of the body. In the single specimen cut for the 

 examination of the ventral fin rays they do not appear as 

 paired structures, but as massive median expansions of the 

 hyaline laminar tissue. 



It will be noticed that the modification which characterises 

 this species, namely, the prolongation of the notochord and 

 cephalic fin in front, is of an exactly opposite nature to that 



Fig. 1. 



Anterior region of D. indicus, comprisiiif^ ilie oral hood and prse-oral 

 lobe from the left side. The anterior end of tiie neurochord with the 

 eye-spot projects in front of the first myotome. 



Fig. 2. 



Eegion of the atriopore of D. indicus ia ventral view, to show the 

 symmetrical termination of the metapleural folds on either side of the 

 ventral fin behind the v. shaped atriopore. 



which distinguishes Asymmetron, where the notochord 

 and caudal fin extend far behind the posterior limit of the 

 myotomes. 



Locality.— Off Black Pagoda, Orissa Coast; 11 fathoms; 

 January 15th, 1889. 



