T. AIDA. 



specimen measured (5mm. in length * and 0,33mm. in breadth, and its 

 caudal segment 1.8mm. The head is comparatively small and has 9 

 seizing hooks and 10-11 teeth arranged in a single row. The row of 

 one side meets at the top of the head with that of the other side (fig 1 4, 

 a). Each seizing hook has a simple termination like that of Krohnia 

 subtilis (fig 15). The fins are three ; a single pair of lateral fins extend 

 from before the spermatic vesicle to the level of the anterior end of the 

 ovary, and lies equally on the trunk and caudal segments. The caudal 

 fin is narrow and long, its breadth being nearly one half of its length. 

 It is attached anteriorly to the spermatic vesicle. The corona ciliata is 

 elliptic and lies wholly on the trunk segment. The mouth is a transverse 

 slit. 



This species greatly resembles Krohnia subtilis, but is distinguished 

 by its small head, regular row of teeth, the smaller number of the teeth, 

 and some other characters. 



12. Spadella draco, (Krohn.) 

 (Fig 12.) 



Literature : Langerhans (1), Hertwig (2), Grassi (3), Strodtmann (4). 



This is the only species of Spadella ever fished in Misaki Harbor. 

 The wide lateral epidermoidal extension of the large vesicular cells, a pair 

 of large tactile prominences, a pair of lateral fins, two rows of teeth, etc. 

 distinguish it from other species. 



In conclusion, I wish to tender my thanks to Prof. Dr. K. Mitsu- 

 KUEi for valuable advice and aid. 



* Among the chaetognat'.is from the Boniu Islands, collected by the late Mr. Hirota, 

 I found one specimen of this species, which differs, however, from those of Misaki in 

 some points. It is a young individual, but its body is I3mm. long. The corona ciliata 

 is more elongated posteriorly, like that of Sagitta negletta. The lateral fins extend on 

 the trunk segment nearly one half as much as on the caudal segment. 



