504 



BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



is very broad, and by maintaining its width forward more strikingly 

 than usually, renders the sides of the snout much more convex dis- 

 tally than in other species with a similarly long snout; its preocular 

 length is contained 2.25 times in head ; its preoral length, 2.6 times ; 

 its width at base, 2.75 times in head, 1.2 times in preocular length; 

 the width of snout at the end of the ethmoid region of the infra- 

 orbital ridge is equal to the length of snout anterior to that point. 

 The ridges of the head are prominent; the occipital ridges are but 

 little divergent forward and backward; the least distance between 

 them is contained 1.2 times in the distance between either their an- 

 terior or posterior ends, and is just half the least interorbital width. 

 The preopercular margin is denticulate; the subopercle is produced 

 backward into a sharply pointed flap. The orbit is smaller than 

 usual in this group, its length being contained 4.25 times in head, 1.9 

 times in snout, 1.35 times in postorbital. Least interorbital width, 



Fig. 25. — Coelorhynchus weberi. Type. After Radcliffe (" Coelorhynchcs 

 commutabilis, form eta "). 



1.45 in postorbital; least suborbital width, 2.35. The upper jaw ex- 

 tends from below the middle of anterior nostril backward to below 

 the hind margin of orbit; its length is contained 4.05 times in the 

 head; barbel, 4.2 in postorbital. Teeth villiform, in bands on jaws. 

 Six branchiostegals ; gill-membranes with a narrow free fold across 

 isthmus. 



Distance from anus to base of outer ventral ray, two-fifths longer 

 than orbit, contained 3.0 times in length of head; distance between 

 ventral and isthmus, nearly one-third longer than orbit, contained 

 3.35 times in length of head; distance between anus and isthmus, 

 1.62 in head. 



Scales large: in 4£ series between the lateral line and the origin 

 of the second dorsal (excluding the lateral line series), in 5^ series 

 a short distance behind that point; the number then decreases pos- 

 teriorly. Each scale of the body is well armed by from 5 to 7 

 strongly spinous carinae. The spinules are long and strong, but 

 not grooved and widened basally as in C. smithi (fig. 20) ; their 

 number is 5 to 7 on the median carina, which is slightly stronger 



