68 E. LE ROY MICHAEL. 



features with certainty. Fowler's papers, accurate and careful 

 in most details, offer, by far, the best aid to the systematist. The 

 characters used are carefull}^ chosen and tested by an examina- 

 tion of a large series of individuals of each species. Anyone 

 attempting to work on this group will find both the Biscayan and 

 Siboga Reports of this investigator invaluable. 



In the genus Sagitta I have adopted the synonymy of Fowler 

 ('06), who recognizes eighteen valid species, as shown in the 

 table at the close of this paper. In addition there are several 

 doubtful species : Sagitta Jiispida Conant, ^. tenuis Conant, .S". 

 maxima Conant, S. bedfordi Doncaster, 5". scptata Doncaster, 5. 

 elegans Verrill, and vS. arctica Aurivillus. Descriptions of these 

 species have been so incomplete and drawings so few that, upon 

 the available data, it is impossible to determine their validity. 5. 

 arctica is very possibly a synonym for S. clcgans but, until the 

 original specimens can be redescribed, it is best to leave them in 

 the category of doubtful species. Of all the doubtful species 

 Verrill's 6". elegans appears to be the most valid, but so little is 

 defined in the description that it will not be included in this paper. 



Of the eighteen species only a few have, as yet, been found in 

 American waters. Sagitta hexaptera, S. enflata, and the doubt- 

 ful species vS". elegans, S. tennis, S. maxima, and 6". hispida have 

 been recorded from the Atlantic Coast, by Conant ('95, '96), Ver- 

 rill ('83), and Stevens ('05). The genus Spadella is represented 

 by two species, Spadella draco, and the doubtful ^. schizoptera 

 Conant. Krohnia is represented by the single species Krohnia 

 haniata. The collections of the University of California from the 

 San Diego region of the Pacific Coast, examined by me, contain 

 the following species of Sagitta : Sagitta scrratodoitata, S. setesios, 

 S. enflata, S. hexaptera, S. bipunctata, S. fnrcata, S. ncglecta, S. 

 decipiens, and S. pnlchra. Spadella is represented by the single 

 species Spadella draco, only one individual having been taken. 

 Krohnia has not, as yet, been recorded. 



Most of the material, which I have examined, consists of a 

 large number of specimens obtained from the coast of Southern 

 California by the explorations of the San Diego Marine Biological 

 Laboratory, and from the collections made by the "Albatross" 

 in the explorations of the United States Bureau of Fisheries on 



