66 University of California Publications in Zoology. [Vol.8 



2. Width of Anterior Fin. It was impossible to measure the 

 width of anterior fin in the single specimen I had occasion to 

 examine. Assuming, however, that Conant's (1895) measure- 

 ment of 3.8 per cent is correct, we find that a variation from 

 2.9 to 3.8 per cent is no greater than the individual variations 

 in this regard of some of the San Diego species. S. en /lata 

 varies from 1.0 to 2.8 per cent, *Sf. hipunctata from 1.4 to 2.5 

 per cent, and many of the other species show as great variations. 

 It is evident that this difference does not signify the existence of 

 two species. 



3. Width of Posterior Fin. The width of posterior fin of 

 S. rohusta is 3.7 per cent and that of S. hispida is 4.9 per cent. 

 Nearly every San Diego species, however, presents a much 

 greater variation. In S. hipunctata the fin varies from 3.1 to 

 4.5 per cent, in S. planktonis from 3.1 to 5.4 per cent, and in 

 S. enflata from 2.6 to 5.7 per cent. It is probable, therefore, 

 that this difference is only a measure of individual variation 

 and not of specific difference. 



4. Number of Anterior Teeth. Conant (1895) records the 

 number of anterior teeth as 4 to 5, while in S. rohusta there are 

 5 to 10. This looks like a more significant difference. Let us 

 see how it bears comparison with other species. In individuals 

 of S. serratodentata varying in length from 6 to 14 mm., Fowler 

 (1905, p. 59) records the variation in anterior teeth as 3 to 6. 



TABLE 23 

 Variation in Anterior Teeth in S. serratodentata 



In the "Siboga" Report (1906, p. 20), however, he finds a 

 variation from 5 to 10 corresponding to individuals of similar 

 lengths. Even a careful comparison of the number of anterior 

 teeth recorded in the Biscayan and "Siboga" Reports, as given 



