486 



BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



The scales are la roe, in but -ti series from the origin of the second 

 dorsal to but excluding the lateral line series; an additional series 

 is inserted shortly behind the origin of the second dorsal. The 5 

 to 7 widely divergent carinae on each scale of the body are armed 

 with about 6 very strong, broad spinules, imbricate, and increasing 

 in strength posteriorly, the last one often projecting a little beyond 

 the margin of its scale; the spinules of the median series are often 

 much larger than those on the lateral carinae. The scales on the 

 spinous ridges of the head are greatly strengthened. The dorso- 

 terminal and ventroterminal plates are armed by 3 to 5 divergent 

 carinae, and are scarcely produced beyond the lateral contour of th'e 

 head. There are 7 to 9 scales along the ethmoid portion of the 

 infraorbital ridge on each side; the 9 to 11 scales on the preorbital 

 portion of the ridge are largest below the front margin of the orbit, 



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Fig. 1.6. — Coelorhynchus platorhvxchus. Type. After Radcliffe. 



and bear spinules mostly confined to their lower margins and to a 

 single vertical series; the scales of the suborbital and preopercular 

 portions of the ridge — that is, behind the vertical through the mid- 

 dle of the eye — are arranged in two series; the distance between 

 the end of the infraorbital ridge and the preopercular margin is 

 contained 1 (3.5 to 5) times in the postorbital length. The scales 

 between the orbit and the infraorbital ridge are small; those from 

 the nasal fossa to below the middle of eye are irregular in position 

 and somewhat strengthened, while those below the posterior half 

 of the orbit, and backward to the preopercular ridge, are regularly 

 arranged, and bear mostly a single spinous ridge directed backward 

 and downward. A series of 10 to 12 scales covers the median su- 

 perior rostral ridge, extending backward to between the verticals 

 from the front of orbit and the front of pupil ; each of these quadrate 

 scales is armed by 3 to 7 spinous carinae radiating outward and 

 backward from the middle of its front margin. 



The occipital ridges are covered by modified scales in the form of 

 elongate tubercles bearing one or two keels, which are armed by 



