25 



beneath the preorbitav. The lower jaw is perforated by 

 two small pores on each side of the cliiu ; and three clus- 

 ters of still smaller ones on cacli limb of the jaw, con- 

 taining from five to eight or ten in each cluster. The teeth 

 are disposed in pretty broad, densely villiform bands on 

 the jaws, divided at the symphyses by a fine smooth line. 

 Those of the outer row above and below are subulate, 

 a little taller than the rest, incurved at the tips, and pretty 

 closely set. There are no teeth on the palate, vomer, or 

 tongue. A few very minute papillre are visible on the 

 chevron of the vomer, but the roof of the mouth is smooth, 

 and without plaits. 



The preorbitar, preoperculum, interoperculum, suboper- 

 culum, and supra-axillary plate of the coracoid bone, are 

 all regularly serrated on their edges. The cheek, having a 

 squai-ish, or slightly rhomboidal form, and a height ex- 

 ceeding the diameter of the orbit, is densely covered with 

 small scales. The scales on the interoperculum and gill- 

 cover are larger. The disk of the preoperculum is a nar- 

 row crescent, with the upper limb longer than the lower 

 one. The teeth of the lower limb are very minute, and 

 incline slightly forwards ; those of the upper one point 

 obliquely upwards ; and towards the middle of the curve, 

 they become sensibly larger. These teeth, as well as 

 those on the other opercular pieces, have intervening acute 

 furrows running a short way on the surface of the bone, 

 but all this is concealed in the recent fisli, by the nacry 

 integument. The operculum is notched at its apex by a 

 crescentic sinus, with acute flat tips, the lower of which is 

 the largest. There are from seven to ten or more teeth on 

 the supra-axillary plate of the coracoid bone, the number 

 of teeth varying in different individuals. A patch of scales 

 exists in the middle of the plate, the rest of its disk being 

 clothed with nacry skin. The scapula is oblong, smooth 

 and entire, but the supra-scapular bone is entirely covered 

 by the scales, which do not difler from the others. 



The scales are strongly ciliated, and present, when in 

 situ, a rhomboidal disk. The lateral line is traced within 

 the upper third of the height, and parallel to the back, as 

 far as the end of the dorsal, where it makes a short curve 

 downwards, and pursues its course along the middle of 

 the tail. It is composed of fifty-four scales, exclusive of 

 some small ones on the base of the caudal, and there are 

 about twenty rows of scales in the vertical height of the 

 body. A fillet of scales runs along the base of the dorsal 

 and anal fins, spreading more broadly on the jointed rays, 

 but not concealing the spines when recumbent. 



The spinous part of the dorsal fin is much arched, the 

 fifth and sixth spines being the tallest, and exceeding half 

 the height of the body. Tlie spines are alternately right 

 and left, and diminish in height from the sixth to the last, 

 which is as short as the third one. Their height and 

 thickness varies a little in different individuals. The 

 soft rays are even, and higher than the posterior spines, 

 and the last one is divided to the base. The second 

 and third anal spines are equal to each other, and nearly 

 twice the height of the first one, but are overtopped 

 by the soft part of the fin, which is shaped like the corre- 

 sponding part of the dorsal. The ventrals are under the 

 middle of the pectorals, or fourth dorsal spine. The 

 caudal is shallowly crescentic at the end. 



The colours of the fish have, doid)tless, undergone con- 

 siderable alteration from maceration in spirits, but the 

 scales still retain a bright silvery lustre, with lines cor- 

 resjjonding to the number of rows. This silvery hue is 

 unstained on the belly. The top of the head, back, and 

 upper part of the sides, have a brownish tinge, and are 

 thickly speckled with darker brown spots, which become 

 gradually effaced on the sides. There is a dark mark under 

 the eye, and two or three rows of brown spots exist on the 

 dorsal and base of the caudal. The upper edge of the 

 soft dorsal is marked anteriorly by a dark patch,* and a 

 broad jet-black bar crosses each horn of the crescent of 

 the tail obliquely. There are also two brown longitudinal 

 bars in the middle of the tail. 



The length of the longest specimen is six inches. 



Hab. Harvey River (fresh water), Western Australia. 

 Good specimens were presented to the Museum at Haslar, 

 by Mr. Bynoe, and also by J. Gould, Esq., the author of 

 the Ornithology of Australia. 



Datnia ? AMBIGUA. Richardsou. 



Radii:— Br. 6; D. lO;— 11 ; A. .3|'J ; C. 15^; P. 16; 

 V. 1|5. 



Plate XIX., natural size. 



I have had much doubt as to whether this fish should be 

 placed in the genus Dules, or Dalnia. It agrees with the 

 group of Dules which have two opercular points, in the 

 number of dorsal rays, and in the presence of palatine 

 teeth, but in general habit it is more like Dnliiiit, strongly 

 resembling it in the strength of its dorsal and anal spines, 

 and in the number of rays in the anal. The only two 

 specimens that I have had an opportunity of examining 

 are dried, and are both mutilated in the caudal fin, so that 

 I am unable to describe the form of that member, and can 

 give no anatomical details. 



Form compressed, the thickness of the body being 

 about half the height, which is greatest at the commence- 

 ment of the dorsal, and a little exceeds one-third of the 

 length of the body, caudal excluded. The back is more 

 acute than the belly, and the pelvic region is flat. In 

 profile the upper cui-ve much exceeds the ventral one. 

 The shoulder is rounded, the face concave, and the descent 

 of the profile, from the dorsal fin, considerable, the mouth 

 being in the lower third of the height. 



The length of the head equals the height of the body, 

 and the lip of the gill-cover is in the line of mid-height. 

 The nape is considerably elevated above the scapular 

 regions. The small round orbit, having a diameter of 

 only one-sixth of the length of the head, is close to the 

 profile, and its diameter is one-third less than the slightly 

 convex space between the eyes. The anterior and smaller 

 nostril is placed midway between the eye and the tip of 

 the snout. The top of the head is scaleless, and the bones 

 of the cranium show through the dried skin, but exhibit 

 no peculiar sculpture. The maxillary is wide and tmn- 

 cated at its lower end, and narrows gradually to its articu- 

 lating extremity. The lips fold back on the jaws, and 



This patch is omitted in the figure. 



