G. HEEBEKT FOWLEE. 



this latter is developed, however, varies much in specimens from other localities. 

 There seems no reason to regard these two points as sufficiently important to justify 

 the separation of Antarctic specimens from D'Orbigny's species. 



Formulae, based on thirty-four specimens : — 



Sagitta serrato-dentata. 



Sagitta serrato-dentata, Krohn, Archiv fiir Naturgeschichte xix. (1853), p. 272. 



As will be shown below, this is not a truly Antarctic form. It appeared to be 

 male-ripe at about 12 mm. of total length ; no really female-ripe specimens occurred. 

 Formulae, based on 8 observations : — 



