175 



2. Fam. EXOCOETIDAE. 



Elongate, more or less compressed. Maxillaries free from or 

 merely adherent to intermaxillaries, which do not form a 

 triangular expansion, but have a straight transverse anterior 

 margin. The symphysis of the lower jaw is sometimes prolonged 

 into a small knob, which projects somewhat before the upper 

 jaw, but generally the jaws are subequal. Teeth rather small 

 or minute, rarely tricuspid, in the jaws and sometimes on 

 palatines, by exception also on vomer, pterygoids and tongue. 

 Pectorals inserted rather high up, very long, forming an organ 

 of flight and consisting of many rays, the first or the first and 

 second of which are undivided. Ventrals short, moderate or 

 long, in the last case assisting the pectorals in suspending the 

 fish in the air. Dorsal far back, beginning above, or behind 

 origin of anal ; both fins of about equal length or the dorsal 

 longer than the anal. Caudal deeply forked, the lower lobe 

 the longer. Scales large or moderate. Lateral line running low 

 down. Gillopenings wide, gillmembranes not united with isthmus. 

 Third upper pharyngeals simply coalescent, the plate readily 

 separating into its two components. 



Distribution: All tropical and subtropical seas, pene- 

 trating more or less into temperate seas during the warm season. 



Key to the indo-australian genera of 

 Exocoetidae. 



I. A large patch of teeth on vomer. Teeth on tongue. 



I.. 1. 38 — 40 Parexocoetus p. 173. 



II. No teeth on vomer or tongue. Teeth on palatines present 

 or absent. L.l. more than 40. 



1. Pectorals comparatively short, not reaching ventrals. 

 Lower jaw prominent, with a symphysial process. 



Ventrals shorter than head Evolantia p. 175. 



2. Pectorals reaching much farther than base of ventrals. 



a. Ventrals much shorter than head, much nearer to 



snout than to base of caudal Exocoetiis p. 177, 



b. Ventrals as long as or longer than head, much 



nearer to caudal than to snout Cypsilunis p. 179. 



I. Parexocoetus Bleeker. 



(BleEKER, Ned. Tijdschr. Dierk. III. 1866, p. 107 and 126). 



Elongate, compressed. Mandibles with a long triangular 



