LIST OF THE NEW SPECIES OF FRESH-WATER FISHES DISCOVERED BY THE LATE M. MOUHOT IN SIAM AND CAMBODIA.
By Dr. Albert Günther.
1. Toxotes microlepis.
D. 5/13. A. 3/17. L. lat. 42. L. transv. 6/14.
FRESH-WATER FISHES.
In the general habit and in all the generic characters the present species completely agrees with T. jaculator; the snout, however, is much shorter, its length being scarcely more than the diameter of the eye, and considerably less than the width between the orbits. The diameter of the eye is one-fourth of the length of the head. The length of the base of the anal equals exactly that of the dorsal. One of the largest scales covers two-thirds of the eye.
The colour may prove to be subject to as much variation as in the other species. The specimens described are yellowish, with greenish back and yellowish caudal. There is a series of four black blotches on each side: the anterior is the smallest, and situated on the upper extremity of the præoperculum; the third is the largest, and placed opposite the dorsal spines; a narrow blackish band round the base of the caudal; a round black spot on the posterior angle of the dorsal; the anal and the ventrals are black.
(Günth., Fishes, ii. p. 68.)
2. Eleotris siamensis.
D. 6 | 10. A. 9. L. lat. 90.
Twenty-two longitudinal series of scales between the origin of the posterior dorsal and the anal, forty transverse ones between the anterior dorsal and the snout. The height of the body is contained six times and two-thirds in the total length, the length of the head four times. Head broad, depressed, with the snout obtuse; the lower jaw is prominent, and the maxillary extends to behind the vertical from the centre of the eye. Teeth in villiform bands. The diameter of the eye is one-seventh of the length of the head, one-half of that of the snout, and of the width of the interorbital space. A small barbel on each side of the upper jaw; the head is covered with small scales; there are about ten between the posterior angle of the orbits; the snout is naked. Dorsal and anal fins much lower than the body: one-half of the caudal is covered with thin scales; its length is contained five times and a half in the total. Brown: the lower parts whitish, minutely punctulated with brown: two oblique dark stripes on the cheek, radiating from the eye. Dorsal fins variegated with blackish, the other fins uniform blackish; a black ocellus, edged with whitish, on the upper part of the root of the caudal fin.
| Lines. | |
| Total length | 60 |
| Height of the body | 9 |
| Length of the head | 15 |
| Diameter of the eye | 2 |
| Length of the caudal fin | 11 |
(Günth., Fish., iii. p. 129.)
3. Osphromenus siamensis.
D. 7/8. A. 11/33-12/35. L. lat. 42. L. transv. 12/16.
When we take the origin of the dorsal fin as the highest point of the upper profile, and the base of the last anal spine as the lowest of the abdomen, the depth between these two points is one-half of the total length (the caudal not included). The length of the head is three times and two-thirds in the same length. The snout is broader than long, equal to the diameter of the eye, which is one-fourth of the length of the head. The interorbital space is convex, wider than the orbit. Mouth very small, rather protractile; præorbital, with its extremity truncated and serrated: angle of the præoperculum serrated; there are two or three series of scales between the eye and the angle of the præoperculum. The dorsal fin commences nearer to the root of the caudal than to the end of the snout; it has six strong spines, which increase in length posteriorly, the last being longer than one-half the length of the head. Caudal emarginate; the anal is nearly entirely scaly, and terminates immediately before the caudal. The longest ventral ray extends beyond the extremity of the caudal, and has three or four rudimentary rays in its axil.
The colour is greenish on the back, silvery on the sides and on the belly. A black spot on the middle of the body in the vertical from the origin of the dorsal, below the lateral line; a second on the middle of the root of the caudal. The soft dorsal and caudal with brown dots; anal yellowish, with lighter spots, and sometimes with brownish dots.
This description is taken from specimens which are from three to four inches long.
(Günth., Fishes, iii. p. 385.)
4. Osphromenus microlepis.
D. 3/10. A. 10/39. L. lat. 60. L. transv. 12/22.
The height of the body is one-half of the total length (without caudal), the length of the head two-sevenths; the profile of the nape is convex, that of the head rather concave. The snout is somewhat depressed, broader than long, with the lower jaw prominent; the interorbital space is convex, nearly twice as wide as the orbit, the diameter of which is one-fifth of the length of the head, and less than that of the snout. Præorbital triangular, with the lower margin serrated; there are five series of scales between the orbit and the angle of the præoperculum. The entire lower margin of the præoperculum and a part of the sub- and inter-operculum are serrated. The dorsal fin commences on the middle of the distance between the snout and the root of the caudal; its spines are moderately strong, the length of the third being more than one-half of that of the head. Caudal emarginate; more than one-half of the anal fin is scaly; it terminates immediately before the caudal. The longest ventral ray extends beyond the extremity of the caudal, and has three rudimentary rays in its axil. Immaculate: back greenish, sides and belly silvery; the soft dorsal and caudal with brownish dots.
Total length six inches.
(Günth., Fishes, iii., p. 385.)
5. Catopra siamensis.
D. 13/15. A. 3/9. L. lat. 27. L. transv. 5½/13.
The height of the body is contained twice and a third in the total length, the length of the head thrice and a third; head as high as long. Snout rather shorter than the eye, the diameter of which is one-fourth of the length of the head, and equal to the width of the interorbital space. The lower jaw is scarcely longer than the upper, and the maxillary extends slightly beyond the anterior margin of the orbit. Two nostrils remote from each other, both very small. Præorbital and angle of the præoperculum slightly serrated; opercles, throat, and isthmus, entirely scaly. The dorsal fin commences above the end of the operculum, and terminates close by the caudal; its spines are very strong, and can be received in a groove; the fifth, sixth, and seventh are the longest, not quite half as long as the head; the last spine is shorter than the penultimate; the soft dorsal is elevated and scaly at the base. The second anal spine is exceedingly strong, rather stronger and longer than the third, and not quite half as long as the head; the soft anal is similar to the soft dorsal. Caudal fin rounded, slightly produced, one-fourth of the total length; its basal half is scaly. Pectoral rather narrow, as long as the head without snout. The ventral is inserted immediately behind the base of the pectoral; it has a strong spine, and extends to the vent.
Scales minutely ciliated: the upper part of the lateral line terminates below the last dorsal rays, the lower commences above the third anal spine.
Gill-membranes united below the throat, not attached to the isthmus, scaly. Four gills, a slit behind the fourth; pseudobranchiæ none.
The jaws, vomer, palatines, and upper and lower pharyngeals are armed with bands of small villiform teeth. Very remarkable are two large, ovate, dentigerous plates, one at the roof, the other at the bottom of the mouth, in front of the pharyngeals; these plates are slightly concave in the middle, pavimentated with molar-like teeth, and have evidently the same function as the pharyngeal dentigerous plates of the true Pharyngognathi.
Total length 52 lines.
(Günth., Proc. Zool. Soc., 1862, June 24.)
6. Ophiocephalus siamensis.
D. 42. A. 27. L. lat. 65. L. transv. 5/11.
Large teeth in the lower jaw, on the vomer and the palatine bones. The height of the body is contained six times and four-fifths in the total length; the length of the head three times and two-fifths; the length of the caudal six times. The width of the interorbital space is more than the extent of the snout, and two-ninths of the length of the head. Cleft of the mouth wide the maxillary not extending to the vertical from the posterior margin of the eye (in old specimens it probably reaches to below that margin). There are eleven series of scales between the eye and the angle of the præoperculum; scales on the upper surface of the head of moderate size. The pectoral extends to the origin of the anal fin, and its length is less than one-half of that of the head: the ventral is not much shorter than the pectoral; greenish-olive, with darker streaks along the series of scales; a light longitudinal band from the eye to the middle of the caudal fin; two series of alternate darker blotches, one above the light band, the other below; side of the head with three oblique brown bands; dorsal and anal fins with oblique blackish stripes; caudal with blackish spots: the lower side of the head blackish, with white spots. (Günth., Fishes, iii., p. 476.)
7. Mastacembelus argus.
D. 32/60. A. 3/56.
Præoperculum with two or three spines. The maxillary does not extend to the vertical from the anterior margin of the eye. Vertical fins continuous: brownish-black, with white bands and round white spots: a band from the occiput, along the middle of the back, passing into the white margin of the vertical fins: a second band above the eye, interrupted and lost on the side of the back: a third from the angle of the mouth, passing into a series of spots, which is continued to the caudal: another series of spots along the side of the belly; the soft dorsal with a series of six spots: pectoral black at the base and near the margin. (Günth., Fishes, iii. p. 542.)
8. Cynoglossus xiphoideus.
D. 120. A. 98. V. 4. L. lat. 135.
Three lateral lines on the left side, the upper and lower separated from the middle by twenty or twenty-one longitudinal series of scales: a single line on the right side. Two nostrils: one between the posterior parts of the eyes, the other in front of the lower eye. Eyes separated by a concave space, the width of which is more than that of the orbit; the upper eye considerably in advance of the lower: lips not fringed. The length of the snout is contained twice and a third in that of the head, the angle of the mouth being behind the vertical from the posterior margin of the eye, and nearer to the gill-opening than to the end of the snout. The rostral hook terminates below the front margin of the eye. The height of the body is contained four times and two-thirds in the total length, the length of the head five times and a half. The height of the dorsal and anal fins is two-sevenths of that of the body. Uniform brownish-grey. (Günth., Fish., iv. p. 495.)