50 U)iiversity of California Puhlications in Zoology. [Vol.8 



5, 5.5, and 6 mm. there is perfect correspondence in the length 

 of the tail in the two species, and in specimens 7 mm. in length 

 iS. neglecta actually oversteps S. regnlaris. Even if taken in 

 their entirety, the total variation Fowler (1906) finds is 26 to 

 40 per cent in 8. neglecta and 28 to 40 per cent in S. regularis. 

 Certainly there is no significant difference in the tail measure- 

 ments of the two species. 



Fowler (1906) also finds a difference in the number of an- 

 terior and posterior teeth, as indicated in table 13. 



TABLE 13 

 Number of Teeth according to Fowler (1906) 



From tliis table we see that the anterior teeth present a differ- 

 ence of only two. The difference in the posterior teeth is 

 greater but, on account of a much larger variation in some 

 species, notably *§. enftata and ^S". hipunciata, it is impossible to 

 feel sure that this difference signifies anything beyond individual 

 variation. 



Fowler (1906) regards the corona ciliata as longer in S. 

 neglecta and extending for some little distance onto the head. 

 In 8. regularis; he finds it is entirely confined to the body. In 

 certain instances, however, he finds the corona of 8. neglecta 

 confined to the body, and in his drawing (1906, pi. 1, figs. 43, 

 44) he represents two lengths of the structure. One would 

 desire to know the variation in length and exact position of 

 this structure before placing much confidence in this criterion 

 for separating two such closely allied forms. 



Finally, it was pointed out that the collarette is much wider 

 and longer in 8. regularis, extending to the anterior fins as in 

 8. planktonis. In no instance was this true of the San Diego 

 specimens of 8. neglecta. 



