120 



and anal rays connected by a membrane. Caudal fin forked, 

 emarginate, truncate or rounded. Scales small 

 or very small. Lateral line running low down, 

 sometimes forming an elevated keel on the 

 caudal peduncle. Gillopenings wide. Gillrakers 

 absent. Lower pharyngeal elongate, narrow, 

 the dentigerous plate scarcely expanded poste- 

 riorly; second and third upper pharyngeals 

 dentigerous; fourth usually distinct, dentigerous. 

 Distribution: West Atlantic, Mediter- 

 ranean, Indie and Pacific. 



Key to the i ndo-aust ralian species 

 of Tylosurus. 



Fig. 48. L lower, // 2^ 

 j>, 4 upper pharyngeals 

 of Tylosunis puuctu- 



A. Caudal truncate or rounded. Lateral line not forming 

 a keel on caudal peduncle. 



1. Anal 2.13 15; D. 2.10 13. Body cylindrical 

 or only slightly compressed. 



a. L. 1. about 170. Caudal with a median black 



blotch T. strongylurus p. 121. 



b. L.I. about 125. Caudal without black blotch . T. macrolepis p. 122. 



2. Anal 2.172.23. D. 2.1418. 



a. Strongly compressed. Origin of ventrals midway 

 between base of caudal and hindmargin of prae- 



operculum. A. 2.1719 T. kre/ti p. 123. 



b. Subcyiindrical or compressed. Origin of ventrals 

 midway between front- or hindborder of eye 

 and base of caudal. A. 2.20 23. 



x. Origin of dorsal above 7th divided ray of 



anal. Head 2.8 3.2 T. leiurus p. 124. 



/3. Origin of dorsal above 2nd divided ray of 



dorsal. Head 2.5 2.7 T. incisus p. 125. 



B. Caudal forked. Lateral line forming a keel on caudal 

 peduncle. 



1. Canines of upper jaw curved forwards. D. 2.20 22. 



A. 2.18 20 T. annulatus p. 126. 



2. Canines of upper jaw vertical. 



a. D. 2.23 24. A. 2.20 21. P. I. II 12 T. melanotus p. 



b. D. 2.19 21 ; A. 2.18 19. P. i .13. 



a. Tongue covered with tubercular asperities. 



Eye twice in postorbital part of head. ... 7! crocodilus p. 

 /3. Tongue smooth. Eye 2.6 2.8 in postorbital 



part of head T. punctulatus p. 129. 



127. 



128. 



