HARRIMANIA MACULOSA 1 29 



3. The presence of ' lateral septa ' in the former and their 

 absence in the latter. 



4. The presence of dorsal ' roots ' to the dorsal collar nerve 

 cord in the former and their absence or imperfect development 

 in the latter. 



My own contributions are as follow^s : 



1. The persistence of the esophageal notochord in the adult 

 animal in Harrhnania^ and its non-existence in Ptychodera. 



2. The persistence in full development of the proboscis pores 

 in Harrimania and the disappearance, usually, of one of them 

 in Ptychodera. [Spengel was in doubt about the primitiveness 

 of this character.] 



3. The presence of genital pleurae in Ptychodera^ generally, 

 and their absence in the Balanoglossid^e. Other characters 

 having, with somewhat less certainty, the same significance 

 might be presented, but to my mind these are sufficient to place 

 the matter beyond the reach of successful attack. 



Such questions as that of the significance of the peculiar re- 

 lation of the gill slits to the esophageal notochord as seen in such 

 a form as Harrimania ; of the reasons for the disappearance of 

 this portion of the notochord in most species ; of the probable 

 significance of it in the light of Masterman's studies on the 

 Diplochorda ; and of various others of a speculative nature I 

 must leave untouched for the present. 



University of Cai<ifornia, 

 Berkeley, Cawf. 

 June 2, 1900. 



