It was until recently supposed that the Poku did not extend its range far north of the Zambesi; but in 1890 Mr. Alfred Sharpe met with it on the Luapula north of Lake Mweru, and says (Pr. R. G. S. n. s. xiv. p. 39) that it is common there, although unknown in the countries bordering on Lake Nyasa. Mr. Sharpe sent home three flat skins and several pairs of horns of this species, which were examined by Sclater (P. Z. S. 1892, p. 98; 1893, p. 728), and says, in his accompanying notes, “I doubt if game can be anywhere more plentiful in Central Africa than in the Mweru and Luapula countries. Cobus vardoni and C. lechee run in enormous herds. These two Antelopes are frequently found together, are much alike in appearance, and are both known by the natives as ‘Nswala.’ (The Impala is also called ‘Nswala’ by them.) The horns of the Letchwé have a much larger spread than those of Vardon’s Antelope, but at a distance it is difficult to distinguish between the two. The Letchwé has a little black stripe on the fore legs which is not found in Vardon’s Antelope. A noticeable feature about the male Letchwé is that when he runs he puts his head down, laying back the horns. Vardon’s Antelope does not do this.” Mr. Sharpe also met with C. vardoni occasionally near the south end of Lake Tanganyika. In the narrative of his second journey to Lake Mweru in 1892 (Geogr. Journ. i. p. 526) Mr. Sharpe has again noticed the abundance of the Poku in the Mweru swamp along with the Lechee.
Our figures of Cobus vardoni (Plate XLI.) were drawn by Mr. Smit from the mounted specimens of both sexes in the British Museum procured by Mr. F. C. Selous at Umparira, on the River Chobe, in 1881. There are skins and skulls in the same collection obtained by Mr. Sharpe and Mr. Crawshay in the district of Lake Mweru.
December, 1896.
68. THE SENGA KOB.
COBUS SENGANUS, SP. N.
Similar to C. vardoni in most respects, but very much smaller (height at withers in a female, measured in the flesh, 30½ inches). General colour rather darker than in C. vardoni, especially on the head. Ears black, tipped behind for fully one-third of the length, instead of merely at their extreme tip. No white ring above the hoofs.
Horns unknown.
Skull measurements of the type (♀), not fully adult, although enceinte when killed:—Basal length 8·9 inches, greatest breadth 3·75, orbit to muzzle 5·85.
Hab. Senga, Upper Loangwa River, W. of the N. end of Lake Nyasa: altitude 2500 feet.
This Antelope, the second member of the genus lately discovered and recognized by Mr. Richard Crawshay, seems to be a small highland form of the Poku, and it is possible that intermediate specimens between the two may be hereafter found. In this case C. senganus will have to be reduced to a subspecies of C. vardoni. But until such intermediate forms are obtained we do not feel justified in presuming their existence, and therefore class C. senganus as a different species.
The only specimen of C. senganus as yet procured is unfortunately a female, young enough still to retain its milk-dentition. The general development of the skull, however, and the fact that, as we are informed by Mr. Crawshay, there was a nearly mature fœtus within the womb, show that the animal had practically attained its full growth, and therefore that its small size may be justifiably used as a distinguishing character.