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REPORT ON ZOOLOGY, MDCCCXLII : 
mail whicli were found in South America, do not belong to the Mega- 
therium, but to a peculiar genus which he calls Olyptodon. Lund, at 
the same time, gave to it the name Holophorus, and D’Alton that of 
Pachypus. 
Orycterotherium missotiriense is a new species described by Harlan. 
The bones were found by Koch on the Missouri ; the teeth are like those 
of the Megalonyx ; the claws like those of Orycteropus. (Sillim. Amer. 
Journ. xlii. p. 392 ; and in Ann. x. p. 72.) 
Harlan, in Sillim. Amer. Journ. xliii. p. 141, quotes Owen’s article, 
Megatheriidce, in the Penny Cyclopaedia, xv., where are five genera 
comprehended ; — Megatherium, Megalonyx, Glossotherium, Mylodon, 
and Scelidotherium. He also puts us in mind, that he had proposed, in 
1835, the name Aulaxodon or Pleurodon, for Mylodon. The latter of 
these two is evidently better than Mylodon, which signifies nothing else 
than grinder. Orycterotherium would also belong to the family Mega- 
theriidcE. 
Lund has given some excellent remarks on the Brazilian ArmadiUoes. 
(Det K. Danske Vidensk. Selsk. Afh. viii. p. 55, 65, 225.) He distin- 
guishes a species, Dasypus uroceras {D. 8-cinctus, Linn.), from Dasypus 
longicaudus (D. ^-cinctus), of the Prince of Neuwied ; it has eight 
molars, eight bands, and tail somewhat shorter than the body. He has 
also discovered a smaller species, called by the Indians Tatu-mirim. 
Mayer has called attention, in his Neuen Untersuch aus der Anat. 
and Phys. p. 32, to a small nipper-like organ, under the tip of the 
tongue of the Dasypus. 
Owen has illustrated the anatomical relations of the Monotremata in 
the third volume of Todd’s Cyclopaedia. The internal structure of these 
remarkable animals is here very clearly and fundamentally shown, with 
many illustrative plates. Whoever wishes to become acquainted with 
tlieir anatomy cannot select a better guide than this article. 
SOLIDUNGULA. 
The Natural History of Horses. By Col. Ham. Smith. (The 
Naturalist’s Library, vol. xii.) 
The author has brought forward no fewer than twelve species of 
horses — a. The Eqiiine form : 1. Equus cahallus domesticus : 2. E. 
varius : 3. E. hippagrus. — h. The Asinine form : 4. Asinus equuleus : 
5. A. onager: 6. A. hamar : 7. A. hemionus. — c. The Hippotigrine 
form : 8. Hippotigris zebra : 9. H. antiquorum : 10. H. Burchelli : 
11. H. quacha : 12. H. isabellinus. — E. varius is the spotted horse, which 
Moorcroft, Gerard, and others mention. From the species, our Piebald 
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