TABLE FOR IDENTIFICATION 



193 



isation. He recognises three other distinct species: S. pontica 

 Ulianin, from the Black Sea ; S. marioni Gourret, from the Gulf 

 of Lyons ; and S. draco Krohn, Mediterranean and Madeiran, and 

 from the Canaries. 



Much confusion has been introduced into the classification 

 of the Chaetognatha by Grassi, 1 who calls some but not all 

 of what other writers term Sagitta, Spadella, and vice versd. 

 The following table was compiled by Strodtmann, 2 but I have 

 incorporated in it two species recently described from Amboyna 

 by Beraneck, 3 and called by him Sagitta bedoti and Spadella 

 vougai respectively : 



CHAETOGNATHA 



I. Two pairs of lateral fins ; two rows of spines on the head ; slender forms. 

 (i.) Number of spines in posterior row greater than in anterior. 

 a. Border of hooks smooth, their point not curved. 



a. No interval between the two fins on each side. 3*5 cm. long ; 4-7 

 anterior spines, 8-11 posterior spines; olfactory organ lying 

 entirely on the trunk. The anterior nerves of the ventral 

 ganglion lie close to one another as far as the head. Sagitta 



LYRA. 



/3. A distinct interval between the two fins on each side. 



aa. Adult animals large ; hooks 6-7 ; anterior spines 

 3-4 ; posterior spines 5-7 ; tail J or ^ of the total 

 length ; lateral areas relatively larger. Sagitta hex- 



APTERA. 



bb. Greatest length 1-2 cm. 



aa. Thickening of the epidermis behind the head ; pro- 

 minently projecting vesiculae seminales ; olfactory 

 organ very long ; hooks 8-10 ; anterior spines 4-6 ; 

 posterior spines 10-15. Sagitta bipunctata. 



/?/?. No epidermal thickening ; two caeca on the an- 

 terior end of intestine ; length 1 cm. ; hooks 6-9 ; 

 anterior spines 3-4 ; posterior spines 7-8 ; point 

 of the hooks somewhat bent round. Sagitta 

 minima. 



yy. Epidermis thin ; no caeca ; hooks 8-9, their ends 

 not bent ; anterior spines 3-4 ; posterior spines 

 7-8 ; length 2 cm. ; small head ; trunk propor- 

 tionately thick. Sagitta enflata. 



88. Hooks 11-14, usually 12; length 1*8 cm.; anterior 

 spines 6-7; posterior spines 18. Sagitta fal- 

 cidexs. 



1 I Chetognati, Flora u. Fauna d. Golfes von Neapel, Mon. V. 1883. 

 2 loc. cit. 3 loc. cit. 



VOL. II 



