415 



are still stronger, their single series is expanded near the 

 symphysis into a semilunar band of three or four series. Gill- 

 membranes united, free from isthmus. Gillopenings forming a 



n.' 



Fig. 212. Head of Macro trema caligans (Cant.). (After CANTOR). 

 e eye ; g gillopening ; // linea lateralis ; n anterior, n' posterior nostril. 



single aperture, which is very wide and extends up the sides 

 to the lateral line. Four branchial arches, all with well 

 developed gills. 



Distribution: that of the single species. 



i. Macrotrema caligans (Cant.). 



Symbrancktts caligans Cantor, Journ. Asiat. Soc. Bengal XVIII. 1850, p. 1316. 

 Ophisternon caligans Bleeker, Act. Soc. Sc. Indo-Neerl. VI. 1859, p. 180. 

 Synbranchus caligans Bleeker, Atl. Ichth. IV. 1864, p. 119. 

 Symbrancktu caligans Giinther, Cat. Brit. Mus. VIII. 1870, p. 17. 

 Symbranchus caligans von Martens, Preussische Exp. nach Ost-Asien, Zool. 



Theil I. 1876, p. 405. 

 Macrotrema caligans Tate Regan, Ann. Mag. Nat. Hist. (8) IX. 1912, p. 390. 



Height at occiput 3 ! / 2 times in length of head, at the anus 

 4 ! / 2 times. Head 8 ! / 2 to 8 3 / 4 . Tail 4 to 5 in head and trunk. 

 Eye minute, nearly opposite to the middle of lip. The dorsal 

 commences opposite to anus, but is not distinct on the anterior 

 third of the tail. The anal resembles the dorsal. Head above 

 and back impure lake-coloured with livid reflections, lighter 

 on the sides and abdomen; throat pale livid; dorsal, anal and 

 caudal pale carmine. Length 200 mm. [After CANTOR; not 

 seen by us]. 



Nomen indig. : Balut (Malay.). 



Habitat: Singapore. - - Pinang. 



In sea. 



3. Synbranchus Bloch. 



(BLOCK, AuslSnd. Fische IX. 1795, p. 87). 



Body naked, elongate, cylindrical; the tail greatly compressed, 

 short and tapering. Lateral line present. Lips well developed, 

 the lower one reverted over the lower jaw. Posterior nostrils 



