1911] Michael: Ckaetognatha of the San Diego Region. 67 



ill table 23 does not show a single ease of overlapping in the 

 entire series. 



Again, Fowler (1906, p. 9) finds the nnmber of anterior 

 teeth in *S^. enfiata greater than we have found in San Diego 

 specimens of the same lengths. Table 24 shows that, as in the 



TABLE 24 

 Variation in Anterior Teeth in S. enfiata 



Length of specimen in mm. "Sibogca" area San Diego region 



20 8-9 5-6 



17 8-9 6-7 



16 8 6-7 



15 8-9 6-7 



12 9 6 



case of S. serratodentata, there is not a single case of over- 

 lapping. 



Finally, in S. sihogae we discover a similar difference between 

 those species obtained by Fowler (1906) and those taken by 

 Ritter-Zahony (1909b). This difference is illustrated in table 25. 



TABLE 25 



Variation in Anterior Teeth of S. sihogae 



Length of specimen in mm. Fowler (1905) Ritter-Zahony (1909) 



11 7 10-12 



10 7 9-11 



9 8 7-13 



Similar instances might be given, but enough has been said 

 to prove that a wide variation in number of anterior teeth 

 occurs in individuals of the same species. Furthermore, in the 

 cases cited, the difference is greater than that found between 

 8. hispida and S. rohusta. 



Considerable space has been utilized in this discussion of 

 teeth relations because Fowler (1906) saw in this difference a 

 reason for not identifying the two species in question. He re- 

 marked upon the similarity betwen the two forms and after 

 identifying Aida's *S'. hispida with S. rohusta concluded (p. 20) : 

 "At any rate it is apparent from the marked difference in 



