21 



1 1 . Sagitta Sibogae species nova. 



Characters. Head large, separated from the body by a well marked neck, with a 

 very short collarette. Body firm, thickest about the middle third, tapering gradually fonvard, 

 more rapidly backward. Longitudinal muscles strong and rather opaque-, lateral fields conspicuous 

 and fairly wide. Tail segment narrow, about 21 to 33 per cent. of the total length. 



Anterior fins long, widest posteriorly (not so wide as in Bedoti), diminishing slightly 

 anteriorly; they reach to the abdominal ganglion; rays(?) absent from the anterior part. Owing 

 to shrinkage inwards of the lateral fields, the anterior fins are often hardly apparent. Posterior 

 fins broader than the anterior, but shorter : about equally distributed on tail and trunk, widest 

 near the plane of the septum ; ceasing far short of the' vesiculae seminales. Tail fin truncate, 

 reaching the vesiculae seminales. 



Jaws for the most part slender and comparatively straight; the first (youngest) with unusually 

 strong base and somewhat more curved ; their tips simple and rather large. Anterior teeth short, 

 with broad bases. Posterior teeth long, broader and with narrower bases than in Bcdoti. 



Corona ciliata not observed with certainty. \'estibular ridge with numerous large papillae, 

 which are higher, more regular, and not so sharp, when compared witli those of Bcdoti. Eyes 

 with elongated pigment. Formulae : — 



6 8 22 



5 — 6 9 — 10 17 — 20 



6 9 20 



6 II 22 



6 9 20 — 23 



6 9 20 



5—6 7—10 18—23 



5—6 8—9 17 



6 8 — 9 16 — 22 



5 — 6 9 — 10 19 — 21 



6 8 — 9 17 — 19 

 5—6 8—9 15—18 



6—7 8 15—17 



7 7 16 



6713 

 s 8 16 



