200 MARSUPIALIA. 
This beautifully coloured Opossum was first described by Mr. Waterhouse from a 
specimen without locality in the collection of the 13th Earl of Derby, in whose honour 
it was named!. Three years later Dr. v. Tschudi described and figured his D. ornata 
from a Peruvian example?; but an examination of his diagnosis and plate clearly shows 
that this animal was specifically identical with Mr. Waterhouse’s specimen. ‘The nearest 
ally of D. derbiana appears to be the Paraguayan D. lanigera, Desmarest, a much smaller 
species, in which only the terminal third of the tail is naked. 
The range of Derby’s Opossum extends northwards from Peru and Ecuador, where it 
has been obtained by Frazer and Buckley, to Central America—there being a specimen 
in the British Museum which was obtained by Arcé at Chepo, in the State of Panama, 
and one in the Berlin Museum from Nicaragua. This latter State seems to be its 
northern boundary, as it is not included in any of Messrs. Godman and Salvin’s collec- 
tions; and it is probably not a common species in any part of Central America. 
Our Plate represents a female Derby’s Opossum with three young ones, living in 
the Zoological Society’s Gardens in May 1877; and is taken from an original sketch 
from the life by Mr. Smit, for which I am indebted to the kindness of Mr. Sclater. It 
well illustrates the way in which the young of the pouchless Opossums cling to the back | 
and flanks of their mother, both by their claws and by their prehensile tails. When 
this female was excited or annoyed, her naked pink ears flushed to a deep rose-colour ; 
and she always showed herself ready to do battle in defence of her helpless family. 
6. Didelphys murina. 
Didelphis murina, Linneus, Syst. Nat. i. p. 72 (1766, descr. orig.)"; Waterhouse, N. H. Mamm. i. 
p- 508°; Frantzius, Arch. f. Naturg. xxxv. 1, p. 318°. 
? Didelphis cayopolin, Gmelin, Linn. Syst. Nat. i. p. 106 (1788, ex Hernandez)’. 
? Coyopollin, Hernandez, De Quad. Nov. Hisp. fol. 10, cap. xxix. 
Tlacuazin raton of Guatemalans. 
Hab. Mexico (Waterhouse*); Guatemata, San Gerénimo (Godman & Salvin, Mus. Brit.), 
Coban (Sarg, Mus. Brit.; Mus. Berol.); Costa Rica (Frantzius*); Panama, Veragua 
(Arcé, Mus. Brit.).—Sovra America to Brazil 2. 
In the Neotropical region the place of the absent placental Insectivores is filled by 
several very small species of Lidelphys. Of these the Murine Opossum is the best-known 
and most widely distributed, its recorded range extending from Southern Mexico to Guiana 
and Eastern Brazil. In Guatemala the 7/acuazin raton is a rare animal. Mr. Sarg’s 
specimens were obtained in hollow trees; one of these, now in the British Museum, 
is an unusually large male, its head and body measuring six inches and its tail nearly 
eight inches. | 
ln spite of its small size, this species does not confine itself to a purely insectivorous 
diet, but preys also on small birds; Temminck found feathers in the stomachs of several 
