36 



In this also the lateral caudal spines are nearly as uniformly 

 large as the medial ones, thus forming three rows, which 

 run farther up the back than in lemprieri. 



Disk rhomboido-ovate : the snout not projecting beyond 

 the angle of the rhomb, but slightly pointed through an 

 undulation in the foi'e edge of the disk, which rounds off 

 laterally into the ovate posterior half Its breadth is in 

 proportion to its length, exclusive of the ventrals, as 6 to 

 55. Tail depressed, flat beneath, rounded above, with a 

 faint indication of a blunt mesial ridge, the sides sloping 

 into a thin cuticular edge. 



The dorsal fins, of equal size and height, are closely 

 approximated to each other, and to the lip of the tail, the 

 posterior one being joined to the very small caudal hy a 

 minute fold of skin. The tip of the tail is acute, and is 

 rendered three-edged by its lajleral cuticular margins, and 

 the scarely more developed caudal fin on its upjjer surface. 

 This fin is highest in the middle, but even there its height 

 does not equal the breath of the tip of the tail. The ven- 

 trals are folded, and irregularly toothed on the edge by 

 cuticular points corresponding with the rays. A narrow 

 anterior obtuse lobe is separated from the rest of the fin 

 by a notch, which penetrates nearly half way to the base; 

 the margin of the posterior portion is rounded, with a 

 somewhat acute hinder comer. The claspers are fusiform, 

 and are overlapped at the base, together with part of the 

 fore lobe of the ventrals, by tlie posterior corners of the 

 pectorals. 



The tip of the snout, a patch before each eye, part of 

 the cheeks, the anterior borders of the disk, the top of the 

 head, middle line of the back, and upper surface of the 

 tail, with the dorsal fins, are thickly set with fine prickles, 

 which point backwards. The cuticular space between 

 the pectorals and snout, the flanks, the posterior half of 

 pectorals, with the exception of a small patch, the ventrals, 

 and the whole under surface of the fish, are smooth. 

 About seven stronger spines arm the supra-orbitar ridge, 

 others are scattered near the anterior edge of the disk, op- 

 posite to the eyes, seven or eight occupy the mesial line 

 between the head and humeral cartilage, and a row, begin- 

 ning at the pelvis, runs down the middle of the tail, having 

 an alternate direction to right and left, not shown in the 

 figure. There are also some scattered larger .spines on the 

 sides of the tail among the smaller ones, but no continuous 

 lateral rows, such as appear in the figure of Raia nasuta, 

 above referred to. Our specimen exhibits two rows of 

 very acute spines, each enclosed in a sheath and pointing 

 niesiad, situated in the widest part of the disk, a little way 

 from the edge. These are probably peculiar to the male 

 in the spawning season. The nasal flap, as is usual in the 

 genus, is adnate in the middle, with a free rounded lobe at 

 each nostril, set with a short fringe. The nostril is capable 

 of being closed by the expansion of a loose fold from its 

 outer border. Cleft of the mouth moderatelj' arched for- 

 wards, and pretty wide. The teeth are round disks, with 

 a central conical cusp, but on the lower jaw many of the 

 cusps are worn away. Both these forms of teeth are 

 shown magnified in the plate. 



The tip of the snout above and below, and the point of 

 the tail beneath, are black : the general colour of the 

 upper surface of the fish is blackish-grey ; the lateral 



regions of the snout and the edges of the pectorals are 

 flesh-coloured, and the under surface is almost wholly 

 white. 



Length of specimen, nineteen inches. 



Hab. Port Arthur, Van Diemen's Land. 



Urolopiius ephippiatus. Richardson. 



Plate XXIV., about two-thirds of the natural size. 



Outline of the disk rhomboido-oval, somewhat broader 

 than long, and much like that of U. aurantiacus, but less 

 wide, and bounded anteriorly, not by convex lines, but by 

 straight ones, which round broadly ofiF into the oval poste- 

 rior portion of the disk. The hinder corner of the pec- 

 toral is more decided than in aurantiacus, being nearly as 

 conspicuous as in the Torpedos. The tip of the snout is 

 an obtuse angle, without the apiculus of auranliacm. 

 Ventrals rounded, united beneath, so that their conjoined 

 margins form a dee\> curve. Caudal fin oval, both lobes 

 nearly equally high, and the under one scarcely running 

 farther forward than the upper one. About thirty carti- 

 laginous rays shine through the integuments of each lobe. 

 The caudal spine occupies more than two-thirds of the 

 width of the tail at its insertion, tapers to a very acute 

 point, is striated on its anterior surface, and strengthened 

 behind by a rounded keel, which fits a depression in the 

 tail. Its edges are serrated by very acute reverted teeth. 



The greatest thickness of the disk is at the junction of 

 the shoulder-girdle with the spine, and from this place the 

 vertical diameter lessens both longitudinally and laterally. 

 The eyes are of moderate size, and have rather a lateral 

 aspect. Their posterior halves are embraced externally by 

 the spout holes, which exceed the orbits in size, and are 

 widest behind. A small valvular fold projects within the 

 spout-hole from its orbital wall, the rest of its lining is 

 smooth. The united nasal fla]) has a straight free edge, 

 and is fringed by obtuse cuticular processes, invisible to 

 the naked eye. The base of the flap is slightly narrower 

 than its free border, and its bridle springs from the middle 

 of the upper lip. In the plate the flap is shown in two 

 positions, when hanging down, and when drawn up. A 

 small rounded lobe projects into the nasal opening from 

 its under border. Folds or streaks are disposed in a 

 doubly pectinated order on the lining of the nostrils. 



When the mouth is gently open, the dental plates occupy 

 the entire borders of the transverse or slightly arched 

 rictus, the teeth rolling a little farther out in the middle of 

 the lower jaw. Individually the teeth are rhomboidal, 

 with the transverse diameter rather exceeding the longi- 

 tudinal one, and having a flat or slightly tumid disk, with- 

 out ridges. Edge of the upper velum straight, and finely 

 fringed, like the nasal flap. Lower velum furni.shed with 

 three or more soft, smooth, conical papilla;, which di.sap- 

 pear as the integuments are moved or stretched. Many 

 pores which exist in the disk and tail are shown in their 

 proper positions in the figure. 



Genital canal transversely plaited, the tapering cornua of 

 the uterus shaggy, with long, filamentous, crowded villi. 

 Liver large, and when the belly is slit up, nearly concealing 

 the intestines, granular, and divided into two oval lobes by 



F 2 



