330 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



DKSCRIPTIOIV OF A T'iE'W AOOIVOID (ACJONtTS VIJr.SUS), FROm 

 TBIE COAST OF CAI^IFOICXIA. 



By DAVID S. JORDAN ntal CHARLES II. GII.BERT. 



Body elongate, tapering rapidly to the long tail, everywhere broader 

 tliaii liigli. It is highest and broadest at the shoulders, but is lower 

 and narrower than the head. 



Head acutely triangular as viewed from above, the profile irregularly 

 sigmoid ; lower surface of head and body plane from the head to the tail. 

 Mouth U-shaped, entirely inferior, the maxillary reaching to opiiosite 

 the front of the pupil, the i^remaxillary in front to the base of the pos- 

 terior pair of rostral spines. The distance from the anterior margin of 

 the premaxillaries forward to the tip of the rostral spines equals more 

 than half the length of the snout, more than half the diameter of the 

 eye, less than one-fifth the length of the head. Lips thickish. Upper 

 jaw protractile. Teeth small, in a villiform band, none evident on the 

 vomer or palatines. Maxillary mandible and branchiostegal region 

 with some small scattered cirri ; under side of snout with few barbels or 

 none. Eyes large, nearly as long as snout, 3| in length of head, the 

 orbital bones forming a raised ridge around them. Interorbit al space 

 transversely concave, nearly straight longitudinally, with a lengthwise 

 groove and two slight ridges. Profile depressed at the front of the eyes, 

 thence nearly straight to the tip of the rostral spines. 



Spines on head highly developed. On each side a stout straight ros- 

 tral spine projecting horizontally forwards; at its base a stout spine 

 curved backwards, upwards, and outwards; behind this a smaller one 

 projecting ujjwards. Orbital ridge above serrated, and with two promi- 

 nent recurved spines, one in front, the other behind ; behintl these a 

 ridge on each side confluent with the dorsal ridges and each with four 

 spines; between these the top of the head is roughish and somewhat 

 concave, with traces of a median keel. At the occiput is a conspicuous 

 pit between the above-mentioned ridges, broader than long and longer 

 than deej). Just below these ridges, on each side, is another and more 

 prominent ridge, also ending in four spines, the last very strong ; this 

 is continuous with the upper lateral keel of the body; below tliis, on the 

 opercle, is a strong keel ending behind in a spine; still lower is an 

 irregular ridge, armed with two or three irregular series of spines and 

 tubercles, extending from the preorbital along the subortal and ])reop- 

 ercle, ending in a stout preopercular spine ; behind the pectorals this 

 ridge again appears as the long lateral keel of the bod5\ 



Along the lower margin of the i^reopercle are three or four more blunt- 

 ish spines. There are on the head between seventy and eighty more or 

 less developed spinous processes. 



Isthmus rather wide. 



Body with four ridges on each side, formed by the series of scales. 

 Each scale ending in a strong recurved spine, its roots forming strii^on 



