72 



E. LE ROY MICHAEL. 



of the pulp into the point, and the pattern of the pulp. Unfortu- 

 nately all known species were not studied by Krumbach. His 

 method should certainly be extended to the remaining species. 

 His classification is here briefly summarized. 



The nine species of Chaetognatha studied by Krumbach ('03) 

 were Sagitta bipunctata, S. ejiflata, S. hexaptera, S. furcata, S. 

 serratodentata, S. minima, Spadella draco, Krohnia hamata, and 

 Sagitta magna, the latter, according to Krumbach ('03), and 

 Fowler ('06), probably being a variety of 5. hexaptcra. These 

 several species Krumbach divides into four groups as follows : 



Group i (Figs, i and 2). 

 Point pt with an oval base b : strongly needle-shaped. Pulp p 

 extends along the central axis of the shaft. Upper third of shaft 



strongly bent. This group includes 

 two species, Sagitta bipnnctata, and 

 Spadella draco. 



Sagitta bipnnctata (i). 

 Point pt imbedded one third its 

 height into the shaft sh. Shaft with 

 fine longitudinal furrows on the sur- 

 faces between the back bk and the 

 edcre eg. 



Spadella draco (2). 

 Flat broad edged crest cr on edge of shaft. Point // inserted 

 one fourth to one fifth its height into shaft. Old jaws- have ser- 

 rations on the lower end of the shaft, which dwindle in size as 

 they approach the point, disappearing entirely while still some 

 distance from the point. 



Group 2 (Figs. 3, 4 and 5). 

 Point // with an oval base b. Back of point b/cpt has greater 

 curvature than the back of the shaft bk ; edge of point egpt and 

 edge of shaft eg have the same curvature so that the junction of 

 the back and edge of the point at the apex lies toward the edge. 

 Pulp p runs slightly nearer the back of the shaft bk. Shaft evenly 



