Lower orbital margin prominent, a pair of spines at its posterior extremity, the hinder the larger.

Preoperculum with a spinulose longitudinal ridge, ending in a backward-directed spine; a second smaller spine below this, at angle; lower limb with two flat angular projections.

Operculum striate, with a ridge, ending in a spine, on its upper part. Occipital and lateral ridges of upper surface of head prominent, spinulose or denticulated above, but without spines; lateral ridges each formed of three shorter ridges; no pit on occiput.

Gill-membranes continuous below, without isthmus; branchiostegals five, large.

Pectoral very long, boldly rounded on its posterior and lower margins, broad; the upper rays slightly increasing to about the sixth, the five lowest decreasing rapidly. Tips of the longest rays reaching nearly to or beyond the sixth dorsal ray, or to the back of the thirteenth or fourteenth dorsal scute. Longest rays about equal in length to the head. Rays simple, base slightly oblique.

Ventrals inserted on the plane of the upper pectoral axil, longer than the pectorals, their greatest length about 4 times in the total length, and consisting of a spine and two rays, the spine attached to the first ray, which is of considerable length, but shorter than the second, the tip of which extends beyond the second anal ray. Membrane between the two rays broad; the second ray fringed with a membrane along its internal margin.

First dorsal commencing at about the eighth dorsal scute and terminating at the sixteenth. First spine shorter than the second, the next five about equal in length, the remainder diminishing rapidly. Height of the longest spines somewhat exceeeding the depth of the body below the fin.

Second dorsal about equal in height and similar in form to the first, arising at about the nineteenth dorsal scute, and terminating at or near the twenty-seventh. First ray shorter than the second, the next four nearly equal, the remainder falling rapidly.

Anal commencing directly below the last ray of the first dorsal, and coterminous with the second dorsal, its lower margin nearly straight, and its depth rather less than the height of the second dorsals.

The last rays of the dorsals and anal are joined to the body by membrane.

Posterior margin of caudal convex; accessory rays few.

Dorsal scutes 35-36, the two series approaching and uniting a little behind the second dorsal; about seven scutes between the point of junction and the caudal.

Each scute produced posteriorly into a large spine bent backwards, and frequently denticulated upon its anterior or outer edge. Behind the point of junction of the two dorsal rows the spines are in closely coupled pairs.

Lateral series of scutes each consisting of 34-36 plates, each armed with a spine similar to those above described.

Ventral series containing 29-31 plates, the last three or four single, the remainder forming a double series similar to the dorsal series, but with less conspicuous spines.

The ventral series commences at the axils of the ventral fins, and the lower surface between these fins and the gill-openings is occupied by several large, separate, subcircular, strongly striated scales or plates, those running along the margin of the gill-openings placed closer together, and forming a series of about seven.

About seven pairs of subcircular scales, not striated, or only slightly striated, are scattered along the acutely triangular space behind the ventrals, between the two ventral series of scutes, which do not fairly meet each other anterior to the anal fin. An elongate naked area behind the pectorals, separating the lower lateral from the ventral series. Some small scales in the space between the mandibles, and a series of small, elevated, and sharp-pointed scales along the curve of the pectoral base.

Vent not far behind the base of the ventrals.

The center of the interocular space, the area between the occipital ridges, some spaces on the lateral aspect of the head between the more prominent parts of the bones, and the areas between the large scales in front of the ventral are set with numerous prickles, a few of which also occur in the intermandibular area.

Similar prickles are numerous on the anterior portion of the trunk, occupying the spaces between the parallel dorsal and upper lateral series of scutes; those of the upper surface end at the first dorsal, those of the upper lateral surfaces at the posterior extremity of the same fin. Behind these points the scuta of these surfaces closely interlock.

Lateral line continuous; a pore between each pair of scutes; pores simple.

Color. After exposure to alcohol, the upper and lateral surfaces of the body are banded alternately with dull yellowish and olivaceous brown; pectorals whitish on their basal portion, a dark spot on the upper and another on the lower edge excepted, and dark on their terminal part, the margin of the dark color running obliquely from the center of the first to the tip of the eleventh ray.

Ventrals with a large black spot on the membrane inside the first ray, and two small spots near the tip of the membrane. Abdomen yellowish white.

When somewhat fresher, the dirty yellowish tint of the ventrals was bright orange yellow, and the black of that fin was more positive, so that it is probable that in life the colors of the whole body were much brighter than they are now.

The total length of the specimens examined, from tip of lower jaw (mouth closed) to tip of caudal, varied from 5.68 inches to 6.65 inches.

Actual measurements of the parts are not given, as the proportions vary but little.

Several examples were collected November 26, 1879, at a depth of ten fathoms, in Drake's Bay, 35 miles north of San Francisco, by Mr. Voy, who has presented them to the State University, Berkeley, Cal.

One of the types is in the United States National Museum, numbered

This species is referred to the genus Brachyopsis, proposed by Dr. Gill for the reception of Agonus rostratus.

This genus is distinguished from Agonus by the projecting lower jaw and consequent comparatively large terminal mouth, and by the absence of an isthmus.

DESCRIPTION OF A NEW GENUS AND SOME NEW SPECIES OF CALIFORNIA FISHES (ICOSTEUS ÆNIGMATICUS AND OSMERUS ATTENUATUS).

ICOSTEUS.

By W. N. LOCKINGTON.

Fam. BLENNIDÆ (?).

Body much compressed. Teeth in a single row in both jaws, close-set, sharp. No teeth on vomer, palatines, or pharyngeals. Gill-openings continuous under the throat, composed of flexible rays, the anterior simple.

A single long dorsal fin; anal similar. Base of pectorals fleshy. Ventrals thoracic in position. Lateral line with groups of spines. Pseudo branchiæ.

Body scaleless throughout; fins beset with spinules along the rays. Etymology: Etzw, to yield; oσreov, bone.

Icosteus ænigmaticus.

Body much compressed throughout; head thicker than any portion of the body. Dorsal outline rising rapidly to the origin of the dorsal; thence more slowly in a regular curve to about the center of the length of the body; thence curving gradually downward to the caudal peduncle. Abdominal outline regularly curved.

Upper and lower outlines of caudal peduncle concave, the peduncle widening posteriorly to support the fin-shaped caudal.

Greatest depth about 33 times in total length; length of head about 5 times in total length; eye 6; snout more than 3; interorbital width about 2 times in the length of the head; caudal peduncle about 5 times in the greatest depth.

Nostrils simple, elongate-elliptical; eyes lateral, their diameter less than the length of the snout; mouth-opening rather large, horizontal, or nearly so; tip of the intermaxillary below the lower margin of the eye; margin of upper jaw formed of the intermaxillaries only; maxilla

ries narrow throughout, not hidden beneath the preorbital; posterior extremity of the maxillary extending to a little beyond a vertical from the center of the eye.

Teeth in jaws in a single row, numerous, fine, sharp-pointed, closely and regularly set, those in the upper jaw smaller than those in the lower. No teeth on vomer or palatines. No pharyngeal teeth present.

Gill-rakers flexible, few, about half as long as the diameter of the eye on the first branchial arch, diminishing on each successive arch.

Gill-openings continuous under the throat; branchiostegals six. Dorsal commencing at a vertical above the pectoral axil, and consisting of 52-55 rays, all soft and flexible, but some of the anterior ones unbranched. Anterior portion of dorsal low, the rays gradually increasing in height posteriorly, the base of the fin terminating opposite to that of the anal, at about 14 times the least width of the caudal peduncle from the origin of the caudal fin; but the longest rays (last but two or three) extending backwards almost to the origin of the central caudal rays. None of the dorsal rays bifurcate more than once.

Anal commencing opposite the 24th-27th dorsal ray; similar to and about equal in depth to the height of the posterior portion of the dorsal, consisting of 37-40 rays, most of them once bifurcate; its base terminating opposite to that of the dorsal, and its longest posterior rays extending backwards even with those of the latter; three last anal rays diminishing rapidly in length.

Some of the anterior anal rays appear to be unbranched.

Caudal elongate, fan-shaped, the central rays longest, and the posterior margin greatly rounded. Posterior part of caudal peduncle expanded, and forming the larger half of an ellipse, around which the rays are set; the central ones straight, the outer ones curving outward and backward. Accessory rays numerous; principal rays twice bifurcate.

Pectorals with a fleshy base, having a curved posterior border from which the rays radiate, forming a fan-shaped fin; the central rays longest, the others diminishing regularly on both sides. All the rays straight; the seven or eight central ones twice, the others once, bifurcate.

Ventrals inserted a little behind the base of the pectorals, narrow, consisting of a short (spinous ?) and four long rays.

Lateral line conspicuous, curving downwards above the pectoral until, a little posterior to the origin of the anal, it reaches the median line of the trunk, along which it continues till it dies out upon the fleshy base of the caudal.

Groups of small spines along the entire length of the lateral line, the number of spines in each group variable. About 120 groups of spines in the smaller example. No scales upon any portion of the body or fins, but the latter rendered rough by asperities or small spinules; a single series along the base of each ray, and a series along each of its branches. Color.-Purple spots and blotches of irregular shape upon a yellowishbrown ground; the spots largest upon the dorsal region, and becoming

smaller and more numerous near the lateral line. The region above and behind the pectorals beset with numerous purple spots, smaller than those above the lateral line. Beneath the lateral line, on the posterior part of the body, there are no spots, except along the line of the anal; but probably this is the result of exposure to alcohol, which has caused the disappearance of most of the spots from the smaller specimen, the color of which, when fresher, was like that of the larger.

Throat and greater portion of gill-membranes without blotches, but sown with dark points, which occur also over the whole of the body and the interior of the mouth. Fleshy bases of caudal and pectorals with sev eral purple blotches. Fins darker than the body, and showing traces of blotches of a deeper tint, especially upon the caudal.

Vertebræ numerous; vertebral column highly flexible and soft. Cranial bones tolerably firm, those of the face and opercles, &c., highly flexible.

Entire body characterized by a lack of firmness, as it can be doubled up as readily as a piece of soft, thick rag. Swim-bladder large.

I append measurements of the two specimens, but many of these must be regarded as approximate only, in consequence of the distortion arising from the softness of texture of the fish, together with that consequent upon cutting them open shortly after they were first procured.

In the larger specimen the ventrals are partly destroyed, and the tips of many of the dorsal and anal rays are wanting.

The shape of the head in the two examples is very different, doubtless owing to the flexibility of the bones. In the larger the snout is bluff, almost perpendicular, the dorsal outline rises rapidly to the origin of the dorsal, and the tip of the premaxillaries is far below the eye; while in the smaller the dorsal outline slopes regularly from the tip of the snout, which is almost level with the lower margin of the eye, to the origin of the dorsal.