CHAETOGNATHA COLLECTED BY STEAMER ALBATEOSS. 



265 



10 anterior teeth, and 11 to 16 posterior teeth; the Philippine speci- 

 mens show 7 to 9 seizing jaws, 6 to 10 anterior teeth, and 10 to 16 

 posterior teeth. 



Nearly half the Philippine specimens are devoid of the collarette, 

 except for a narrow strip behind the head. This caused consider- 

 able trouble in identification until others were discovered in which 

 the structure was partly missing. These (pi. 36, figs. 12 and 13) 

 indicate that for some unknown reason the collarette has been torn 

 off. Immature specimens in this condition bear a striking super- 

 ficial resemblance to young S. ferox. 



Table 17. — Measurements of Pterosagitta draco} 



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



Distribution.— P. draco was obtained from only five stations, all 

 of which were subsurface ones. Two were mesoplanktonic, but they 

 only yielded four specimens. The remaining 28 were obtained from 

 between the surface and 25 fathoms, indicating that in so far as the 

 species occurs in the Philippine region it is typical of the upper epi- 

 plankton. This accords with what is known of its distribution gen- 

 erally. Although nowhere abundant it is apparently restricted to 

 the upper epiplankton of tropical and subtropical regions. Says 

 Ritter-Zahony (1911, p. 63): "Ihre Verbreitung diirfte sich mit der 

 von S. enfiata und bijiunctata decken, doch ist die Art in den gemassig- 

 ten Zonen, soweit sie iiberhaupt noch darin vorkommt, schon seltener 

 als jene beiden. . . ." Its northernmost and southernmost records 

 of occurrence are 42° north, 56° west; and 42° south, 36° east. 

 Its records of capture during the Philippine expedition are given in 

 the table following: 



59318— 19— Bull. 100 3 



