from “Otro Cerro,” North-eastern Rioja. 499 
Jength 50°5, 43 ; zygomatic breadth 30°2, 27 ; nasals 17°5, 
14:7x 8, 6:6; interorbital breadth 12, 9°38; least breadth 
across brain-case 19°8, 17°8; bi-meatal breadth 31°3, 27 ; 
palatilar length 23°7, 20; length of bulle 17, 15°2 ; upper: 
tooth-series (alveoli) 11:1, 10, (crowns) 10, 9°6. 
Type. Adult male. B.M. no. 19. 2.7.47. Original 
number 338. Collected 27th August, 1918. 
This tuco-tuco is no donbt nearly allied to C. budini, but 
may be distinguished externally by its dark muzzle, more 
buffy sides, and absence of collar, and in the skull by the 
various details above described, and notably by the absence 
of a separate interparietal. 
It is named in honour of Col. C. Morley Knight, by whom, 
in conjunction with his partner Col. J. J. Porteous, the 
explorations of Messrs. Kemp and Budin have been so much 
facilitated in various ways. 
‘“* Found on stony ground.”—E. B. 
13. Lagidium lockwoodi, sp. n. 
2. 333. 
Size comparatively large, about as in L. cuscus. 
General colour nearest to that of ZL. cuscus, of a similar 
deep grey colour, but not quite so dark; darker than in 
L. tucumanum. Dorsal dark line well defined, distinct, 
running from nape to rump. Under surface broadly washed 
with buffy ochraceous; no axillary white patches present. 
Feet grizzled grey, scarcely lighter terminally, Tail distinctly 
black along its under surface, its long crest mixed black 
and dull buffy whitish, the end black. 
Skull decidedly larger than in L. tueumanum, the only 
species geographically near; muzzle larger; nasals little 
inflated anteriorly, aud owing to the great breadth of the 
premaxillaries the latter are visible outside them from above. 
Bony islet above meatus fairly large, nearly square; oblong 
transversely in tucumanum. Posterior line of occiput almost 
straight transversely, scarcely bulging backwards in the 
centre, as it does markedly in every specimen of tucumanum. 
Incisive fissure unusually large and open, 2 mm. in breadth. 
Palatal foramina also widely open posteriorly, in decided 
contrast with those of twewmanum. Bulle much larger than 
in the Tucuman species. 
Incisors yellow in front, unusually large, and heavier, 
