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Show 1902.] PLECTOGXATHOUS FISHES. 303 small specimens of this species with Bleeker's type specimen has convinced me of their specific identity. The supposed difference in the nasal organs is non-existent, they might impartially be described either as a short tube with two terminal lips, or as two tentacles united basally, although the former phrase is more applicable to the smaller specimens, the latter to the larger, as might be expected from what we know of the evolution of these organs. T etrodon pu stul a tu s Murray. The nasal organs in this species are almost exactly similar to those of the closely allied Tetrodon patoca, which has been placed in a different section on account of supposed differences in these organs. T etrodon b o r n e en s is , n. sp. (Plate X X IV . fig. 3.) Nasal organ an elevated tube, very indistinctly two-lipped, with a single terminal aperture. Body rather compressed, with dorsal keel more or less distinct, the caudal peduncle twice as deep as broad and not longer than deep. Length of head about 2f times in the total length; snout not longer than broad, half the length of head ; nasal organs midway between eye and end of snout; eye-diameter 3|-4| times in the length of head, interorbital width about 2-i- times; ethmoid very narrow. Jaws subequal in height, the upper somewhat projecting, with fairly well-marked ridges on each side of the median groove; cutting-edges concave. Spines small, numerous, extending on the head and body from the level of the nostrils to that of the vent. D. 11. A. 10, rounded, not elevated. Caudal rounded. Dark brown above, lighter below. A light cross-band between the eyes is continued forward on each side from the eye through the nasal organ to the end of the snout, and a broader band runs back on each side from the eye to meet its fellow in the middorsal line. Sometimes irregular bands or reticulations on the sides and caudal fin. Dorsal and anal immaculate. Sarawak. Total length 70 mm. E XP LAN A T IO N OP THE PLATES. P l a t e X X IV . Fig. 1. Pseudomonacanthus degeni (natural size), p. 299. 2. Tetrodon pleurogramma (natural size), p. 300. 3. „ borneensis (natural size), p. 303. P l a t e X X V . Fig. 1. Pseudomonacanthus multimaculatus (reduced to / r), p. 298. 2. „ punctulatus (reduced to T7,), p. 298. |
