Bathysaurus Agassizii, Goode, G. B. & Bean, T. H., 1883

Goode, G. B. & Bean, T. H., 1883, Reports on the results of dredging under the supervision of Alexander Agassiz, on the east coast of the United States, during the summer of 1880, by the U. S. coast survey steamer “ Blake, ” Commander J. R. Bartlett, U. S. N., commanding., Bulletin of the Museum of Comparative Zoology at Harvard College 10 (5), pp. 183-226 : 215-218

35. Bathysaurus Agassizii , new species.

Body elongate, subcylindrical, with depressed head and tapering tail, its greatest height contained seven times in its standard length, and eight times in the length to tip of upper caudal lobe: its greatest width nine times in standard length ; its height at the origin of the anal about halt’ its greatest height ; length of caudal peduncle equal to greatest height of body.

Scales irregularly ovate, with the free portion convex, thin, cycloid, leathery, deciduous, those in middle of body with a vertical diameter nearly equal to that of the pupil, those of lateral line with posterior margin truncate. In the lateral line, which extends upon the caudal fin, descending below the median line of the body near the origin of this fin, are seventy-eight specialized scales, larger than those of the body. Between the dorsal fin and the lateral line are about eight rows of scales ; between the latter and the anal fin are about the same number.

Head twice as long as the greatest height of the body, strongly depressed, alligator-like, naked except upon the cheeks and a small area on the occiput, with strong nasal and interorbital ridges. The greatest width is somewhat more than half its greatest length, the width of interorbital area nearly equal to half that of head, and one fourth the length of the lower jaw. The length of the snout is equal to twice the horizontal diameter of the eye. The anterior nostrils are situated midway between the tip of the snout and the anterior margin of the orbit. The cleft of the mouth is enormous, its angle posterior to the eye by a distance about equal to the width of the interorbital space. The length of the upper jaw equals one sixth of the standard body length ; that of the lower jaw, one fifth. The margin of the upper jaw (formed by the intermaxillary only) is armed with two irregular rows of depressible teeth, some of which are barbed ; those in the inner row are much the largest, many of them being two thirds as long as the horizontal diameter of the pupil and twice as long as those in the outer series. The lower jaws are enormous! v O •) o strong, and broad, flattened below, the width measured on the under surface of the head equal to two thirds the width of the broad interorbital space. The lower jaw projects outside of the upper jaw at the sides a distance apparently equal to half its width, and considerably in front ; the lower jaws are thickly studded with depressible teeth, many of them, especially the larger inner ones, strongly barbed, those in front claw-like, recurved. On the palatines, three rows of teeth, the middle ones very much enlarged and most of them strongly barbed, - these being the largest of all the teeth. On the tongue a lew weaker teeth, and groups of similar teeth upon the vomer.

Gill laminae, gill rakers, and pseudobranchise, as described by Dr. Gunther in the diagnosis of the genus.

The dorsal fin contains seventeen rays, and is inserted at a distance from the w / tip of the snout equal to the length of its own base, and slightly greater than one third of the standard body length. The fourth or longest ray is equal in length to the greatest height of the body. The first ray is a rudiment; the second is nearly half as long as the third ; the third slightly shorter than the fourth ; after the fourth the rays diminish rapidly in length to the ninth, which is about half as long as the lower jaw, and subsequent to which the diminution is gradual : the last ray is about as long as the first.

There is no adipose dorsal; if ever present, it was obliterattd before the specimen came into our possession.

The anal fin contains eleven rays, and is inserted considerably behind the vertical from the termination of the dorsal, - at a distance equal to the horizontal diameter of the eye ; the length of its base is equal to half that of the dorsal , the length of its longest ray (the third) equal to that of the eighth of the dorsal.

The caudal is slightly forked, its middle rays two thirds as long as those in the upper lobe, and about equal to the seventh dorsal ray.

The pectoral fin consists of fifteen rays, is inserted under the fourth scale of the lateral line, and at a distance in front of the dorsal equal to half the greatest height of the body. Its length is equal to that of the lower jaw, and the seventh ray is prolonged to a length equal to that of the head, its tip extending to the perpendicular from the twelfth dorsal ray.

The ventral is composed of eight rays, and its base is almost entirely in advance of the perpendicular from the origin of the dorsal : its length equals half that of the head. The two ventrals are far apart.

Radial formula: 13. 10 (?) ; 1). 17 ; A. 11 ; C. 19; P. 15 ; A. 8. Scales 8, 78, 8.

Color brownish, the inside of the branchiostegal flap bluish black.

A single specimen, about two feet in total length, a female, full of nearly mature eggs, was taken at a depth of G47 fathoms, at Station 325, in Lat. 33° 35' 20" N., Long. 76° W.

MEASUREMENTS.

Millimeters.

Length to base of caudal.......540

Length to end of middle caudal rays . . . . 610

Body. Greatest height ....... 76

Greatest width.......58

Height at ventrals ....... 76

Least height of tail.......25

Head. Greatest length . . . . . . .137

Greatest width...... 62

Width of interorbital area .....27

Length of snout.......40

Length of maxillary.......89

Length of mandible......108

Diameter of orbit.......20

Dorsal. Distance from snout.....191

Length of base........171

Length of first ray....... 5

Length of longest ray (4th).....78

Anal. Distance from snout......380

Length of base........85

Length of longest rav......56

Pectoral. Distance from snout......144

Length.........105

Length of prolonged ray . . . . . .132

Ventral. Distance from snout . . . . . 175

Length.........70

Branchiostegals..... X (?)

Dorsal..........17

Aniil • • • • • • • • •. II

Caudal . . . . . . . . . .19

Pectoral . . . . . . . . •. . 15

Ventral 8

Number of scales in lateral line.....78

Number of transverse rows above lateral line ... 8

Number of transverse rows below lateral line . . . 8