274 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



Table 20. — Comparison of number of anterior and posterior teeth in Philippine species 

 and those from the Siboga region — Continued. 



SAGITTA PLANKTONIS. 



SAGITTA PULCHRA. 



SAGITTA DECIPIENS. 



SAGITTA BEDOT1. 



10-12 

 12-14 

 14-16 



SAGITTA FEROX. 



Inspection of this table reveals a pronounced similarity in number of 

 both anterior and posterior teeth between Philippine and Siboga speci- 

 mens of Sagitta enjlata, S. planktonis , S. pulchra, S. bedoti, S.ferox, and 

 Pterosagitta draco. In S. neglecta, S. serratodentata, and S. deciviens 

 specimens from the two regions agree in number of anterior teeth, 

 but those from the Philippines have a greater number of posterior 

 teeth. Even in these instances the differences are slight and prob- 

 ably insignificant except for 8. decipiens. In this species there 

 seems to be no doubt that the Philippine specimens have more 

 posterior teeth than Siboga specimens of the same length, although, 

 as pointed out on page 254, where the length of animal was neglected, 

 Fowler's records show a range of 13 to 23 posterior teeth as against 

 that of 19 to 22 for Philippine specimens. 



