300 Mr. O. Thomas on the Echimy ine. 
Dimensions of the type (measured on skin) :— 
Head and body 225 mm. ; tail 345; hind foot 46°5. 
Skull: greatest length 57; condylo-incisive length 51:4 ; 
zygomatic breadth 29:3 ; nasals 18°2 x 6; interorbital breadth 
12-2 ; palatilar length 23 ; upper tooth-series 15:2. 
Hab. Sierra de Merida. Alt. 2800 m. 
Type. Adult male. B.M. no. 5.7.5.7. Original num- 
ber 17. Collected on 15th December, 1903, by 8. Briceiio. 
Three specimens. 
On the other hand, the specimens from Bogota and Antio- 
quia agree closely with each other in all important respects. 
The last group on which I have any comment to make is 
that of the short-tailed spiny rats, which includes Azara’s 
spiny rat, the first of the subfamily to be discovered, and 
neatly the last to have its technical name settled. For 
Fleming’s selection of EZ. chrysurus as the type of Lchimys 
has dispossessed spinosus of the generic name by which it has 
been so long known, and it must now bear Goeldi’s term _ 
Euryzygomatomys. 
But turther consideration makes me think that its Brazilian 
relative, “‘ Hehimys”’ laticeps, differs so much from it as to 
justify the erection for it of a special genus, which might be 
diagnosed as follows :— 
CLYOMYS, gen. nov. 
Fore-claws fossorial, much longer than in Euryzygoma- 
tomys. 
Bulle hypertrophied, a great part of them visible external 
to the paroccipital processes when viewed from behind. 
Molars proportionally small, the last upper soon losing the 
posterior transverse cleft, so that the tooth-surface is then 
circular, with one notch only on each side of it. In Lury- 
zygomatomys the most worn teeth always show traces ot a 
trilaminate structure. 
Genotype. Clyomys laticeps (Mesomys laticeps, Winge* ; 
Echimys laticeps, Thos.). 
Other distinctions between spznosus and /aticeps are pointed 
out in my paper on the latter, which is the only member of 
the family with distinctly fossorial claws and hypertrophied 
bullee. 
* By the modern rules, the fact that Winge published the statement 
that “ Loncheres laticeps, Lund=Mesomys sprnosus, Desm.,” made him 
the author of the specific name, even though he did not recognize the 
distinctness of the animal from Mesomys spinosus. His description and 
figures of the latter all refer to Clyomys laticeps, 
