OCR Text |
Show 332 DR. A. GtTNTHER ON [Nov. 18, specimens of this species; he collected them on the River Dunkwa, and at Nyankoma, R. Enon. Some of these specimens differ in certain points, as the height of the spinous dorsal fin, the form of the cheeks, &c., from those previously received and among themselves. However, I regard these differences as merely individual variations; they are indicated in the following table, in which measurements are given in millimetres; the teeth are counted on one side of the upper jaw only :- 1 1 1 g> i s Ch. offoivensis: 1 r" Length of head. Length of 8 D. spine. Height of cheek. 1 Length of cheek. 1 Teeth in upper jaw. 00 9) a O < Sp oa CD -M GO •fp-3 Ph P. not reaching A. 1. Lambarene, type ... 170 47 19 12 12 28 11+3 * 2. Kotehwah R .............. 154 CO 16 9 10 23 11+3 # 3. Prah R ....................... 142 36 18 8 10 27 12+4 4. Prah R .......................j 140 35 16 8 10 26 11+4 5. Kakum R .................... 162 42 20 10 13 29 12+5 # 6. Kakum R................... 140 35 18 7 11 25 13+4 7. Kakum R................... 117 30 15 6 9 25 12+4 8. Dunkwa R..................1 130 32 17 7 10 25 11+4 ... 9. Dunkwa R ................. 125 , 32 17 7 10 24 12+4 # 10. Nyankoma.................! 132 33 16 7 10 24 11+3 # 11. Nyankoma.................' 129 33 16 7 11 26 12+5 12. Ch. latus, type ...... 112 28 13 6 9 19 9+ 3 % C hr om is d iscolor, sp. n. D. A. L. lat. 29-30. L. transv. 3/11. Nineteen or twenty teeth on each side of the upper jaw. Maxillary rather short, not extending to the vertical from the front margin of the eye. Upper profile of the snout straight; interorbital space flat, wider than the orbit, which is nearly one fourth of the length of the head. Three series of scales on the regard the size and number of teeth as a valuable specific character which should always be taken into consideration, combined with a statement of the size of the specimens to which the statement of the dental number applies. Therefore I must demur to Mr. Boulenger's statement that in C. ogowensis the teeth " vary " from 15 to 30 on each side (I. c. p. 466). The typical specimen, from which alone my original description is taken, is 170 millim. long, and probably mature. The collector put into the same bottle two young specimens, 62 and 66 millim. long, which presumably may belong to the same species. I say presumably, for I confess that the uncertainty and difficulties attending the determination and specific discrimination of the young of closely-allied species of Chromis are too great to allow me to offer a categorical opinion upon them. |