PHILIPPINE MACROUROID FISHES GILBERT AND HUBBS. 436 



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superior rostral sensory canal by means of a foramen, which is 

 roofed over by a bony arch forming the anterior part of the oc- 

 cipital ridge. From the upper edge of the high median rostral 

 crest of each side there branches off a slender horizontal rod, which 

 supports the skin over a large sense organ. 



The position of the anus is more posterior than in other species; 

 its distance from the base of the ventral fin, 1.95 (1.8 to 2.3) in 

 head; its distance from the isthmus, 1.16 (1.15 to 1.32). The dis- 

 tance between the base of the outer ventral ray and the isthmus 

 is contained 2.7 (to 3.0) times in the head. 



A highly differentiated organ, of problematic function, lies in 

 the body wall on the midabdominal line. It is probably homolo- 

 gous to, but more complicated than, similar structures which we 

 have described in Coelorhynchus and in other genera. As we have 

 found this organ with skeletal support only in this subgenus (Quin- 

 cuncia), its structure is probably diagnostic of the group. A de- 

 scription of this organ follows. A black superficial streak extends 

 forward from the anus, at each end dilated into an area in which 

 the scales are much reduced in size. The distance between the ante- 

 rior end of this black streak and the isthmus is a little greater than 

 half the orbital length. Immediately above this streak, between 

 the ventral ends of the lateral muscles, there is located the organ 

 being described. It consists of a stand of soft tissue, more or less 

 pigmented on its ventral (or outer) surface, firmly united with 

 the peritoneum, and expanded at each end into a depressed dilation. 

 The posterior one is bilobed, being divided by the anus. The thick 

 anterior dilation is roughly triangular in outline, with a convex 

 anterior edge. It lies within a cavity, and is supported in a strik- 

 ingly peculiar manner by a cartilaginous rod in close connection 

 with the pelvic girdle. The posterior arm of this bone is a poorly 

 ossified plate, which by meeting its fellow at the median line, forms 

 a brace directly between the ventral bases. From the anteromedian 

 angle of each of these posterior limbs a cylindrical rod of cartilagi- 

 nous tissue extends forward to the sides of the anterior dilation, 

 from which it extends dorsad, meeting its fellow in a wide arch, 

 the apex of which is bound to the well ossified anterior arms of 

 the public bone, where these meet at the median line. 



Nine pyloric caeca, much shorter than the orbit, were counted in 

 one specimen. 



Shrimp-like crustaceans were found in the stomachs of two speci- 

 mens. 



The lateral line gently rises anteriorly to form a long, low curve, 

 the chord of which is about as long as the distance between the anus 

 and the isthmus. The thin scales are armed with short, stout, sub- 

 erect spinules, which are arranged in quincunx order (occasionally 

 showing a tendency to align themselves to form parallel or divergent 



