164 



chelles, British India and North China to the Philippines, Indo- 

 australian Archipelago, North Australia and the Pacific Islands. 

 In rivers and estuaries. 



Key to the indo-australian species of 

 Zenarchopterus. 



I. Triangular part of upper jaw nearly twice as long 

 as broad 1 ). 



A. Entire head 2.5 2.6 in length. Base of ventrals 

 twice nearer to caudal than to frontborder of 



eye or corner of mouth ............. Z. caudovittatus p. 164. 



B. Entire head 2 2.3 in length. Base of ventrals 

 nearly or quite twice nearer to caudal than to 



branchial opening ................. Z. ectuntio p. 165. 



II. Triangular part of upper jaw i 2 / 7 times as long 

 as broad. Base of ventrals twice nearer to caudal 

 than to hindborder of eye .............. Z. rasori p. 166. 



III. Triangular part of upper jaw about as long as broad. 



A. Anal 10 II. 



1. Head from tip of upper jaw 3 3.3 in trunk. 



D. 14 ...................... Z. novae-guinea e p. 167. 



2. Head from tip of upper jaw 2.3 2.5 in 



trunk. D. 10 n ................ Z. kampeni p. 167. 



B. Anal 13 14. Head from tip of upper jaw 3 in 

 trunk. D. 10 12. 



1. Lower jaw beyond upper jaw 5 times in length. Z. brevirostris p. 168. 



2. Lower jaw beyond upper jaw 3 times in length. Z. dux p. 169. 



IV. Triangular part of upper jaw broader than long. 



A. Base of anal 2 2.4 in that of dorsal, 6th and 

 7th anal ray in males enormously enlarged, often 



reaching to end of caudal ............ Z. dispar p. 169. 



B. Base of anal 2.53 in that of dorsal, 6th and 

 7th anal ray in males enlarged, but not so much 



as to reach to base of caudal .......... Z. btiffoni p. 170. 



i. Zenarchopterus caudovittatus (M. Web.; 



ts (Zenarchopterus) caudovittatus M 

 229. 



D. 12; A. 12; P. 1.9; V. I. 5 ; L.I. 



ffemiramphus (Zenarchopterus) caudovittatus Max Weber, Nova Guinea, V. Livr. 2, 

 1908, p. 229. 



i) Subgenus "Labidorhamphus" Fowler, Proc, Acad. Nat. Sc. Philad. (2) LVII 

 1905, p. 493 



