46 University of California Puhlications in Zoology. [Vol.8 



Ritter-Zahony (1909c, p. 790) says: "Zweifellos ist S. zetesios 

 mit ihr [*S'. pIankfo)iis] identisch, " and I think we must fully 

 agree Avith him. The similarity extends to nearly every point. 

 Fowler (1905, p. 71) records three specimens which he doubt- 

 fully identifies as *S'. planktonis, but states that "they bear a close 

 general resemblance to zetesios." He then points out the fol- 

 lowing differences : In S. zetesius the anterior and posterior 

 fins are closer together, and the former extends farther forward. 

 The widest portion of the posterior fin is level with or behind the 

 tail-septum, the posterior fin is more on the trunk than tail, and 

 the posterior teeth number less for the same length. In all these 

 points the specimens from San Diego are quite variable, except 

 that the posterior fin is more on the trunk than on the tail, 

 which condition is the same as described by Fowler (1905) for 

 jS. zetesios. 



S. planktonis at first sight bears a certain resemlilance to S. 

 hedoti, and *S'. ferox. It is however readily separable from the 

 former by the presence of such a conspicuous collarette, and by 

 the fact that the anterior fin is longer than the posterior one. 

 From the latter it differs in having a greater numbei- of seizing 

 jaws, more than 50 per cent of the posterior fin in front of tail- 

 septum, narrower collarette, and in many of the proportional 

 measurements. It bears some resemblance to S. rohusta, but the 

 body of the latter is proportionally narrower, the collarette is less 

 extensive, and the anterior fin is shorter than the posterior fin. 



Sagitta neglecta Aida. 



PI. 2, fig. 7; pi. 3, fig. 22; pi. 4, fig. 34 



Sagitta neglecta Aida (1897), p. 16; Fowler (1906), p. 15. 

 Sagitta hipunctata, Beraneck (1895), p. 153. 



General Appearance 



In degree of opacity this species bears a strong resemblance 

 to >>. scrratodcntata. It is , however, more slender and pin- 

 shaped. Upon a black background (pi. 2, fig. 7) the head, 

 ventral ganglion, and seminal vesicles appear more opaque than 

 the body. The intestine and ovaries are only slightly different 

 in opacity from the body. The entire tail segment is slightly 



