74 



E. LE ROY MICHAEL. 



curved. This group includes Sagitta liexaptera (6) and 6". magna 

 (7). The latter is, as previously mentioned, now regarded as a 

 variety of S. hcxaptcra. The only difference is that the jaws of 

 5". magna are finer, more slender, and delicate than in an indi- 

 vidual of S. Jiexaptera of the same size. The pulp reaches higher 

 toward the apex of the point than in 5. hcxaptcra. 



Group 4 (Figs. 8, 9 and 10). 

 Point pt sickle-shaped, bent toward the edge of the shaft eg, 

 varying in curvature between the two extremes indicated. Base 

 more or less oval. Pulp p enters the shaft between the center 



-b. 



10 



and the back focus of the cross-section. Pulp reaches nearly to the 

 knee of the point, but never makes the bend. Shaft only slightly 

 curved. This group includes Sagitta niinivia, S. serratodcntata 

 and Krohnia haniata. 



Sagitta minima (8). 

 Jaws slender and long with slender points only slightly set 

 into the shaft. Cross-section of shaft wedge-shaped. Pulp / 

 is swollen siu slightly below the point. Tip of point // bent 

 much more than the rest of the jaw. Old jaws have a small 

 delicate crest. 



Sagitta serratodcntata (9). 



Pronounced serrations scr on the shaft. The first tooth of the 

 serration is the smallest, extending from the top of the shaft / 

 half-way to the basal line of the point b. Proceeding proximally 

 the teeth increase in size. Cross-section of the shaft is an 



