PHILIPPINE MACROUROID FISHES — GILBERT AND HUBBS. 523 



across the isthmus. The short spiny gill-rakers are fewer than in any 

 form previously described with the exception of tenuis, there being 

 but 12 or 13 on the outer two arches ; the first gill-arch is bound down 

 by membrane above its angle and near its anterior end. Seven 

 branchiostegals. 



The anus is located immediately before the origin of the anal fin, 

 its distance from the base of the outer ventral ray being equal to the 

 distance from tip of snout to hind margin of orbit, and a little longer 

 than the distance between the ventral base and the isthmus at the 

 fold of the gill-membranes. 



The two ventral lens-shaped bodies are present in the usual posi- 

 tions ; both are circular in outline ; the diameter of the anterior one, 

 located in advance of the ventrals, is about two-thirds that of the 

 posterior one, which is situated immediately before the anus. The 



Fig. 31. — Hymexocephalus gracilis. Type. 



two organs, as usual, are connected by a black-surfaced strand of 

 tissue along the inner surface of the abdominal body wall. 



The scales are almost entirely lost, but three are present near the 

 origin of the lateral line ; two are overlapped by the last of the scale- 

 like bones flooring the sensory canal in advance of the lateral line. 

 The scales are round and marked with concentric striae, but are 

 wholly spineless. One, bearing a lateral line pore, is separated from 

 the origin of the first dorsal by 2£ rows of scales. 



This species is sharply distinguished from all others of the genus 

 previously described, with the exception of H. tenuis, by the presence 

 of weak denticulations on the distal portion of the dorsal spine ; the 

 spine is broken, but 5 denticulations remain on a distal portion only 

 half as long as the orbit; the proximal smooth portion of the spine 

 is two-thirds the postorbital length. The length of the first dorsal 

 base is about half the interval between the dorsals, or two-thirds 

 the postorbital. The rays of the paired fins are exceedingly slender 

 and weak; the pectoral fin is just equal in length to the postorbital 



