PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 369 



on the opercle, which is faint or obsolete in xanti. In form, structure 

 of fins, numbers of scales, &c., we are unable to find any differences. 



71. Tripterygixun carminale Jor. & Gilb. 

 2487. Two examples. 



72. Salarias atlanticus C. & V. 



2745, 7324, 7333, 7794. Many specimens, of various sizes. 



73. Isesthes gentilis (Grd.) J. & G. 



2481. Two examples, the largest '2h inches long, answering entirely to 

 the description of the female of this species given by Dr. Steindachner 

 (Ichth. Beitr. v, 150). A male specimen of this species is in Mr. Lock- 

 ington's collection, from La Paz. 



74. Myxodagnus opercularis Gill. 



{Hfi/xodagmis opcrculavls Gill, Proc. Ac. Nat. ^ci. Phila. 1861, 263.) 



2531, 2532, 2533. (Types of Myxodagmis opercularis.) Three imma- 

 ture examples, faded. 



75. Dactylagnus miindus Gill. 



{Dactylafjnus mtindus Gill, Proc. Ac. Nat. Sci. Phila. 1862, 505.) 

 4915. (Type of Dactylagnus mundus.) One specimen, nearly 6 inches 

 long. 



76. Sebastopsis xyris, sp. nov, 



30979. Six small specimens, somewhat discolored, the largest about 

 3 inches in length. 



Head 2i; depth 3i. D. XIII, 10 ; A. Ill, 5. Lat. 1. 24 (pores). 



Body oblong, somewhat compressed, the back a little elevated. Head 

 large, very strongly armed. Mouth rather large, oblique, the jaws sub- 

 equal in frout, the maxillary extending to beyond pupil, its length If 

 in head. No i^alatiue teeth. Jaws naked. Preorbital narrow, its edge 

 lobate, not spinous. Eye large, about 3| in head. 



Cranial ridges very short, sharp, and high, their spines more or less 

 hook-like and compressed. Interorbital space narrow, very deeply con- 

 cave, with two curved longitudinal ridges, each armed with a small 

 spine. Nasal spines sharp. Preocular, supraocular, postocular, tym- 

 panic, occipital, nuchal, and coronal spines present. Occipital ridge 

 very short, spine-like. Coronal spines separating the naked frontal 

 region from the scaly part of the head. A sharp temporal spine on each 

 side ; behind it two strong spines on the suprascapula ; a spine on the 

 shoulder-girdle. Opercle with two spines. Preopercle with about five 

 spines, the largest with a smaller spine at its base in front, the two lower- 

 most spines almost obsolete. Suborbital stay forming a sharp elevated 

 ridge, with a sharp spine near its front, under the eye, and another near 

 its junction with the preopercle. Gill-rakers very short, rather stout. 

 Proc. Nat. Mus. 82 24 Sept. 5, 1 882. 



