CHAETOGNATHA COLLECTED BY STEAMER, ALBATROSS. 251 



The single specimen (Cat. No. 17926, U.S.N.M.) was obtained 

 November 6, 1908, in the China Sea, in the vicinity of Formosa, at 

 station D. 5320, 20 58' north and 120 3' east by an open 0000 grit 

 gauze net towed at 3.18 in the afternoon in 500 fathoms for twenty 

 minutes. 



SAGITTA PULCHRA Doncaster. 



Plate 35, fig. 5; plate 37, figs. 19, 23. 



Sagitta pulchra DONCASTER (1902), p. 213. FOWLER (1906), p. 17. RITTER- 

 ZAHONY (1911), p. 21. 



Approximately 500 individuals were obtained, and few, if any, are 

 sexually mature. In body length and number of teeth they agree 

 remarkably well with specimens described by Fowler (1906) from the 

 Siboga region. He records 5 to 10 anterior and 9 to 15 posterior 

 teeth in specimens between 9 and 22 mm. in length, and in Philippine 

 specimens between 9 and 30 mm. in length, the anterior teeth number 

 5 to 9, and the posterior teeth 10 to 13. The Philippine specimens 

 are, on the whole, so well preserved that the species is redescribed. 



Collarette (pi. 35, fig. 5) conspicuous but short, varying in length 

 from one-twentieth to one-tenth the length of the animal. Its 

 length is less than twice the body width and it extends between one- 

 fourth and one-half the distance from neck to ventral ganglion Neck 

 pronounced but rendered inconspicuous by the collarette. Muscles 

 thin but strong. Lateral fields large. More transparent than any 

 other species having a collarette, and similar in transparency to S. 

 enflata. Its body, however, is firmer than that of 8. enflata and is 

 approximately half as wide. Width greatest between one-half and 

 three-quarters the distance from head to tail-septum, tapering 

 gradually forward and more rapidly backward. Slight constriction 

 at tail-septum. Tail 18 to 25 per cent of total length of animal. 

 Corona ciliata not observed. 



Anterior fins (pi. 35, fig. 5) longer and narrower than posterior fins 

 extending anteriorly beyond posterior end of ventral ganglion, 

 frequently beyond its middle, and rarely beyond its anterior end. 

 No rays except in posterior quarter of fin. Interval from anterior 

 to posterior fins usually less than two-thirds width of body, varying 

 from slightly less than one-half to slightly more than the width. 



Posterior fins (pi. 35, fig. 5) rayless anteriorly. They extend 

 posteriorly nearly if not quite to seminal vesicles, the interval 

 never exceeding 2.5 per cent of total length of animal. More than 

 50 per cent of fin in front of tail-septum, varying from 50.5 to 64 per 

 cent. Broadly triangular in form, and widest at or slightly behind 

 tail-septum. 



Vestibular ridge (pi. 37, fig. 19) provided with large regular papillae, 

 the apices of which usually terminate in two minute spines. Wing 

 of ridge covers all except first two or three teeth. Notch extends 



