8 



The table following shows the formulae of Bcdoti, polyodon, and bipunctata of Aiua ; 

 that of bipunctata Quoy and Gaimard, has been added for comparison with the latter. 



It is fairly obvious that the first four agree together and differ from the fifth. Aida's 

 figure of '■bipunctata is quite unlike the outline of European specimens of the species of Quoy 

 and Gaimard, but agrees with that of Bedoti. 



2. Sagitta enjlata Grassi. 



B. Grassi. I Chetognati. Fauna und Flora des Golfes von Neapel: Monographie V, p. 13. 



T. Aida. Op. cit., p. 15. 



L. DuNCASTER. Op. cit., p. 210. 

 ? Sagitta Gardineri Doncaster. 



L. Doncaster. Op. cit., p- 212. 

 ? Sagitta flaccida Conant. 



F. S. Conant. Notes on the Chaetognatha. John Hopkins University Circulars, vol. XV, p. 85. 



Characters. Head rather small in contraction, but quite broad when expanded: it is 

 marked off from the body by a distinct neck; no collarette present. Body tumid, extremely 

 transparent; much thickest about the middle of its length, tapering gradually forward and 

 backward; body very flaccid, owing to the extreme thinness of the longitudinal muscles; lateral 

 fields large. Tail segment about 16 to 25 per cent. of the total length. Ganglion small, about 

 midway between the head and the anterior lui. 



Anterior fins narrow, short, broadest bchind the middle of their length, not nearly 

 reaching to the ganglion. Posterior fins short, broader than the anterior. widest at about the 

 plane of the septum, slightly more on the trunk thun on tlie tail, not nearly reaching to the 

 vesiculae .seminales. Tail fin truncate, reaching the vesiculae seminales when tumid. 



Jaws .slender, strongly curved, with rather small tips. Anterior teeth rather abruinly 

 pointed, closely set. Posterior teeth clear in colour, strong, rather short in comparison to their 

 breadth, abru]>tly ])ointed, with small tips, diverging distally, closely set proximally. 



Vestibular ridge with fairly regular low roundcd prominences, terminating externall\ in 

 a considerable blunt process. Corona ciliata short, almost cntirely on the head, varying (: with 

 the state of contraction or expansion of the head) from a simple sinuous outline to a complex 

 hour glass shape. 



The variation in the corona is very noticeable, and .seems to be due to distortion of 

 the simple form shown in fig. 10. It was not figured by Grassi. 



As in other species of the same flaccidity, the lateral fields shrink inwards in poor 

 specimens, .so that the anterior fins almost disapi)car from view. Formulae: — 



