152 PKOCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



form ; anterior margin descendin o- rather abruptly, obtusely rounded j 

 basal margin somewhat sinuous posteriorly. Surface deeplj^ sulcated 

 for tlie greater portion, the sulci mainly disappearing on the umbonial 

 slope, where they give place to finely crowded strioe; aj^ex acute 5 mus- 

 cular impressions impressed; margin minutely crenulated. 



Length, If inches. (No. 2490.) 



Aquia Creek, Virginia. 



Apeil 25, 1880. 



©ESCKIPTIOIV OF A IVEW^ AG®lVOII> FI!^H (BRACHVOPSIS XYOSTER- 

 IVUS), FBOITI MONTEREV BAY, CAt.IFOK]VIA. 



By DAVIO S. JORDAIV and CMARUCS II. GILBERT. 



Brachyopsis xyosternus sp. nov. 



Form of head and body as in Bracayopsis verrucosus Lockington. 

 Body elongate, depressed, broadest at the shoulders, thence tapering 

 rapidly to the snout, and gradually and evenly to the tail. Snout broad, 

 obtuse, depressed, its sides parallel. Mouth terminal, very oblique, the 

 lower jjw much the longer, its tip projecting upward above the upper 

 profile of the snout. Mandible very broad, its greatest depth one-third 

 its length, maxillary reaching to half way between front of orbit and 

 pupil. A long barbel three-fourths the diameter of the orbit at its end. 

 Premaxillaries anteriorly above the level of the i)upil. Jaws with bands 

 of villiform teeth. Vomer and palatines with slight asperities. Nasal 

 spines i^resent. No spines on top of cranium. Interorbital space broad, 

 concave, from the elevation of the supraocular ridges. Preorbital with 

 two spines. A sharj) spine on the suborbital at lower posterior margin 

 of eye. Preopercle with four processes, the upper one a sharj) sj^ine. 

 Opercle striate, without spine. Top of head and the upper parts of the 

 body without the small prickles Avhich are found in B. verrucosus. Oc- 

 cipital pit obsolete. 



No isthmus, the gill membrane united across the breast. No slit be 

 hind the last gill. 



Body with the usual eight series of long keeled plates. Each keel 

 terminating in a strong spine hooked backward, strife radiating in every 

 direction from the spine. 



Dorsal series of i^lates 32, 6 before the spinous dorsal, 6 along its base, 

 4 between the two dorsals, 5 along the base of the soft dorsal, and 11 

 behind it. The two dorsal series uniting immediately behind the soft 

 dorsal, the resultant single series round, with radiating strise, the kee- 

 and spine obsolete. The two abdominal series similarly unite close be- 

 hind the anal fin. 



The plates in the upper lateral series diminish in size forward, becom- 

 ing very small anteriorly. The lower lateral series becomes broader for- 

 wards as the other series decreases. It terminates abruptly opi)Osite 



