OCR Text |
Show 18^9.] FROM THE GOLD COAST. 727 without knowing more of the changes that must take place during growth. CHRYSICHTHYS NIGRODIGITATUS Lacep. Of this species two specimens are in the Natural History Museum ; it is not known from what West African river they were obtained. One measures 280 millim., tbe other 130 millim. in length, excluding the caudal fin. In spite of the great difference in size, both agree in form of the snout, in the great development of the dorsal fin, prolongation of caudal lobes, number of anal rays (nine branched), &c. Only the eye is very much larger in the younger specimen, as might be expected. In both, the teeth of the palate are confined to the vomer, and appear in the young as two small, oblique, ovate patches ; in the older specimen tbe two patches are produced behind into a narrow tract of teeth. CHRYSICHTHYS PERSIMILIS, sp. n. (Plate XLIII.) Chrysichthys macrops, part., Giinth. Ann. & Mag. N . H . 1867, xx. p. 111. The height of the body is one fifth of the total length (without caudal), the length of the head a little less than one third. Caudal peduncle two thirds as high as long. Head a little broader than high, its greatest depth being contained 1| times in its length. The greater portion of its upper surface is granulated, but covered with a thin film of skin ; occipital process longer than the basal bone of the dorsal spine, both meeting a little behind the middle of the nape. Snout long, three eighths of the length of the head, broad, rather depressed. Mouth of great width, extending to Fig. 7. Chrysichthys persimilis. Upper and lower teeth below the middle of the distance between eye and nostril, much wider than the distance between the eyes. Nasal barbels small and short, about half as long as the eye. Maxillary barbels reaching to, outer mandibulary barbels not reaching to, the gill-opening when stretched backward. Inner mandibulary barbels anterior to the outer, half a diameter of the eye distant from each other. The teeth on the palate occupy vomer and palatine bones, and |