150. PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



eud of opercular flap. Whole upper surface of head covered with small 

 skiuuy tubercles. Vomeriue patch of teeth very large. 



Two stroug spines abov^e the suout, an obtuse promiuenr-e above each 

 orbit ami a pair ou the occiput. In large individuals there is a tendency 

 towards division and enlargement of the i^rominences and their exten- 

 sion, so as to form imperfect keels on the vertex. Behind the supra- 

 orbital prominences are several radiating sharp ridges similar to those 

 of 0. polyacanthocephalus. luterocular space concave. There is also a 

 depression on the vertex, becoming narrower posteriorly. Three pre- 

 opercular spines, the uppermost being longest and equal to the eye in 

 length. The longest dorsal sj)ine (fourth) is half as long as postorbital 

 part of head, or slightly more. The length of the maxillary bone is 

 contained 2^ times in the length of the head. End of maxilla reaches 

 slightly past hind margin of eye. The ventrals when extended straight 

 backwards are equal to their distance from the beginning of the anal. 

 The pectorals reach the vertical from the beginning of the soft dorsal. 

 Skin above the lateral line with a single series of rough bony tubercles 

 which are linely toothed and sometimes depressed in the centre. A 

 few similar but smaller si)iny tubercles below the lateral line. 



The dorsals are separated by a short interspace. The spinous dorsal 

 begins in a line with the upper axil of the pectoral. The longest ray of 

 the second dorsal is contained 4 times in the distance from the tip of 

 the snout to the beginning of the second dorsal. Tail little rounded, 

 contained 5^ times in total length without caudal. 



Colors of the alcoholic specimen: Purplish brown above, whitish be- 

 low. First dorsal has two broad, oblique dark bands separated by a 

 light area. Second dorsal has about 5 dark bands, anal about 6. The 

 pectorals have about 4 interrupted bands ; the caudal has 3. Ventrals 

 whitish, faintly tinged in two areas with dark color. Sides with a few 

 white blotches ; a larger individual has, also, some small w^hite blotches 

 ou the belly. 



Length of type 240 millimeters (9 J inches). 



Length of head ,- 3. 4 



Length of snout 8 



Greatest height of body ... 1. 5 



Least height of tail . . . = 4 



Greatest width of body 1.6 



Width of interocular space 5 



Long diameter of eye •. .5 



Length of fourth dorsal spine 9 



Length of fifth dorsal ray 1.2 



Length of sixth anal ray 9 



Length of i)ectoral 1. 9 



Length of ventral 1.3 



Length of caudal 1.4 



Length of maxilla 1. 4 



