EXPLANATION <>K PLATE LXXI. 



Sagitta austral is, Jnstn. 



Fig. 1. — Entire specimen. 



,, -J. Head. 



,, 3. — Jaw. 



,, 4. — End of a jaw. 



., 5. — Vestibular ridge. 



,, 6. — Transv. sect, in region of ventral gangliou. 



-., 7.— ,, ,, ,, ,, ovary. 



,, 8. — ,, ,, ), ,, anus. 



. . 9. — ,, ,, ,, ,. testes (tail). 



,, 10. — ,, ., ,, ,, vesiculae seminales. 



,, !L— ,, ,, ,, ,, tail fin. 



In the drawing of sections, th ! muscle is lined, the epidermis plain, the 

 intestinal and coelomic epithelium dotted. 



References to lettering: — a.f , anterior fin; a.t., anterior teeth; b., 

 base of point; b.n., buccal nerve; b.p , back of point; br., brain; c, 

 ccelome ; c. ep., coelomic epithelium; d.l.m. , dorso-lateral muscle; d.m., 

 dorsal mesentery ; e., edge of point ; ep., epidermis; e,s., edge of shaft; 

 f., tin ; f.r., fin ray ; g., insertion of base of point ; h., head ; int., intes- 

 tine ; i.e., intestiual epithelium ; i t., inmost tooth of posterior row; j., 

 jaw ; k., anus ; I. p., lateral process of vestibular ridge ; m., muscle ; mo., 

 mouth ; o., ovary ; o.d,, oviduct; o 0., external opening of oviduct ; o.m., 

 oblique muscles ; o.t., outermost posterior tooth ; ph., pharynx ; p., pulp ; 

 p.r., posterior row of teeth ; pt., point of jaw : p.f., posterior fin ; s., shaft 

 of jaw; s.m., sperm morulas; t., tail; i.e., tail ccelome; t.f., tail fin; 

 t.g , testes; t.m., tail mesentery; tr.m., transverse muscle; t.s., tail 

 septum; V.g., ventral ganglion; v.l.m., ventral longit. muscles; v.m., 

 ventral mesentery; v.r., vestibular ridge; w., anterior septum; x., 

 posterior extension of body ccelome behind anus ; y, oesophagus. 



