174 PROCEEDINGIS OF THE ]!iATWi\AL MUSEUM. vol.54. 



species, there being only about 10 in the similar double series of 

 the outerjtwo arches. They are scarcely less rudimentary than in 

 the species of the genera related to Coryphaenoides and Lionurus. 

 The structure of the head is comparatively firm. 



The distance between anus and base of ventral fins equals that 

 between tip^of snout and hinder margin of pupil, and is a httle 

 longer than the distance from base of ventral to fold of the gill- 

 membranes where they cross the isthmus. Laterally the gill- 

 membranes are free from the isthmus. 



The lens-like structure before the anus is longitudinally elliptical 

 in outline, and is a httle longer than the similar but more nearly 

 circular organ on the midventral line before the ventral fins. 



The scales are largely lost, but several are retained along the 

 sides and on the belly. They are all smooth and are marked with 

 numerous concentric striae. About three rows of scales seem to 

 separate the lateral line from the front of the first dorsal fin. 



The distal portion of the second dorsal spine is weakly but dis- 

 tinctly denticulate, as in no other described species of the genus. 

 The base of the first dorsal fin is contained 1.8 times in the inter- 

 dorsal space, 1.3 times in the postocular length of the head. The 

 rays of the paired fins are slender and weak; the outer ventral ray 

 extends not quite to the anus and is contained 1.7 in the head; the 

 inner ventral rays are shorter than the orbit and extend but half- 

 way to the anus. The first anal rays are also shorter than the orbit. 

 Tliere are 8 rays in the ventral fin. 



The ground color is yellowish brown, darkest about the base of 

 the first dorsal fin; a median silvery streak is evident along the tail; 

 the sides of the head and trunk to above the pectoral base are bright 

 silvery in color, separated by an indistinct darker streak from the 

 color of the back. The region before the ventral fins is blackish, 

 with coppery luster near the isthmus. The head is marked by a 

 dark streak along the front of the snout, one along the inner margin 

 of the jaw next the teeth, and one along the crest forming the side 

 of each mandibular ramus. The gular membrane is crossed regularly 

 by fine parallel black lines, which are not separated by silvery streaks 

 and are not to be confounded with the true striae of the abdominal 

 region, which are of rather restricted development in this species. 

 These fine striae extend forward from immediately above the ventral 

 base, fading out along the sides of the isthmus. Behind the ventrals, 

 they can barely be distinguished for a short distance. There are 

 none immediately in front of the ventral base, and none immediately 

 below the bases of the pectorals. The abdominal region is punctulate 

 with very large chromatophores with pearly centers. The sides of 

 the trunk above the silvery region are finely and densely punctulate. 

 The chromatophores on the tail are coarser and sparser, occurring 



