OCR Text |
Show 1906. | FRESH-WATER FISHES OF TRINIDAD. 383 above about the seventh anal ray ; when laid back, in the female not nearly reaching the caudal, in the adult male extending well beyond the base of caudal. Anal 25-30, commencing at or a little behind the middle of the length of the fish; last ray, when laid back, in the female not reaching the caudal, in the adult male extending well beyond the base of the caudal. Pectorals and ventrals extending to or nearly to the origin of anal; ventrals 7-rayed. Caudal deeply forked, the lobes equal in the female, the lower considerably produced in the adult male. Caudal peduncle If-2 as long as deep. Olivaceous, with silvery reflections; a blackish stripe along the middle of the side ; fins pale. 14 examples, measuring up to 45 m m . in total length. The genus Stevardia was founded either on females or on very young males, with the operculum ending in a short pointed process and the fins not produced. Corynopoma included males of small size, with the opercular process short and the fins moderately produced, whilst Nematopoma was for the fully developed males. Liitken pointed out that these supposed generic differences were to be found in examples of the same species, according to the size of the specimen taken. These changes are now found to be confined to the males, and I see no reason to believe that more than one species has formed the basis of Dr. Gill's descriptions. This genus has only been recorded from Trinidad. "The 'Swallow-tailed Sardine' is fairly plentiful in the Tacarigua River. Some have a peculiar pair of ' paddles' attached to the gill-covers, whilst others have no trace of them nor do they have the exaggerated fins which the ones with ' paddles ' possess. They are caught in company and are, presumably, the same species. The scales are faintly defined, generally silvery; the back is translucent greenish." 4. TETRAGONOPTERUS TJENIURUS Gill. (Plate XXII. fig. 4.) Depth of body 3-3^ in the length, length of head 4-4^. Snout much shorter than eye, the diameter of which is 2k in the length of head and a little greater than the interorbital width. Maxillary extending to below the anterior | of eye, with a more 7A or less evident series of small teeth. Scales 38 ^f 5 between lateral line and root of ventral fin ; lateral line complete. Dorsal 10, with 8 branched rays, its origin a little nearer to tip of snout than to base of caudal; anterior rays longest, nearly as lono- as the head. Anal 29-31, with 26 to 28 branched rays. Pectoral extending beyond base of ventral; ventrals originating in advance of the dorsal, extending to the anal. Caudal forked. Caudal peduncle as long as, or a little longer than deep. Olivaceous or greenish above, silvery below; a silvery longitudinal band from operculum to base of caudal; a more or less distinct dark humeral spot; a black longitudinal band on the middle caudal rays, ed^ed with yellow above and below. Here described from two specimens from Trinidad, 60 and |