CHAETOGNATHA COLLECTED BY STEAMER ALBATROSS. 



249 



Length in mm 9. 5. 



Tail: 



Length 20. 8 per cent of length . 



To ventral ganglion 68. 5 per cent of length. 



Posterior fin: 



Length 17. 6 per cent of length . 



To seminal vesicles 3. 2 per cent of length . 



To anterior fin ' 9. 1 per cent of length . 



Proportion in front of tail-septum 59. 1 per cent. 



Anterior fin: 



Length 16. 5 per cent of length. 



To ventral ganglion 11. 7 per cent of length. 



Number of anterior teeth 5-4. 



Number of posterior teeth ll-(?) 



Number of seizing jaws 8-9. 



The other specimen measured 8.9 mm.; its tail measured 20.7 per 

 cent; the number of anterior teeth are 4-5; the number of posterior 

 teeth, 10-10; and the number of seizing jaws, 9-8. 



SAGITTA SERRATODENTATA Krohn. 



Sagitta serratodenlata Krohn (1853), p. 272. — Fowler (1905), p. 58. — Potter 

 Zahony (1911), p. 22.— Michael (1911), p. 39. 



Approximately 100 specimens were obtained, none of which is 

 sexually mature. The number of anterior and posterior teeth is 

 greater than recorded by Fowler (1905, p. 58) in specimens taken 

 from the Bay of Biscay, or by myself (1911, p. 40) in specimens taken 

 from the San Diego region. In specimens between 7 and 11 mm. in 

 length Fowler records 3 to 6 anterior and 2 to 10 posterior teeth, 

 while in Philippine specimens between the same lengths, the anterior 

 teeth number 8 to 11 and the posterior teeth 13 to 24. The San 

 Diego specimens are considerably larger, those recorded varying in 

 length between 10 and 17 mm.; but the number of teeth is inter- 

 mediate, the anterior teeth numbering 6 to 9 and the posterior teeth 

 13 to 19. The species appears to be unusually variable. 

 Table 5. — Measurements of Sagitta serratodentata. 1 



1 All measurements made in per cent of total length of animal. 



2 Per cent of posterior fin in front of tail-septum. 



59318— 19— Bull. 100- 



