MAMMALIA. 685 



liinder pentadactylous ; outer toe short both before and behind. 

 Tail long, annulate, thinly haired. 



Sp. Cercomys cumcularius F. Cuv. Mammif., Livr. 60, Nouv. Ann. clu Mus. 

 I. 1832, pp. 449 — 452, PI. 18, fig. I (molar teeth), PI. 19, figs, i, a (cra- 

 nium), Hab. in Brasil. 



Loncheres Illig., Echimys Geofpe, [EcJiinomys more correctly 



Wagn.). • Incisor teeth smooth; molar j — j, complex. Whiskers 



long, numerous. Spines almost always intermixed with hairs on 

 the back, lanceolate, flat, or concave above. Fore feet tetradacty- 

 lous, with thumb-wart unguiculate, liinder pentadactylous. Claws 

 short, compressed, incurved. Tail long, annulate, more or less 

 hairy. 



Compare on this genua of South American rodents IsiD. Geoffk. 

 Saint-Hilaiee Notice sur les Rongeurs epineux in Guerin Magas. de Zool. 

 1840, Mammif. pp. i — 57, PI, 20 — 29. 



Dactylomys Isin. Geoffr. Fore feet tetradactylous. Two middle 

 toes of fore feet and three middle toes of hind feet much longer than 

 the lateral toes. Tail long, annulate, thinly haired except the base. 

 Spines none. (Each molar tooth composed of two parts divided 

 by a transverse groove; crown of upper molars divided into two 

 triangles, with the acute apex internal, emarginate externally, 

 crown of lower with first part triangular, incised internally, the 

 other part oval.) 



Sp. Echimys dactylinus Desmae., DacUfornys fypus Ibid. Geoffr. I. 1. PI. 



20, Deville in Guerin Hevue et Magas. de Zool. 1852, pp. 354 — 357; 



Dactylomys emhlyonyx Natterer, Wagn. 



Echinomys (Ism. Geoffr.), Wagn, Characters of the genus. 

 Ears elongate, acuminate. Tarsi elongate, narrow. Molar teeth 

 small, with crown rounded. Spines in adidts, mostly mixed with 

 hair, 



Sp. Loncheres cayennensis (FiscH.), Echimys cayennensis Geoffe., Desmae., 

 Loncheres myosurus (and hptosoma) Lichtenst., Guee. Iconogr., Mammif. 

 PI- 24, fig. 3, Waterh. Mamm. 11, PI. 19, fig. 2. (Younger individuals, 

 that had not got spines, occasioned the adoption of a distinct species, 

 Echimys setosus Geoffr., Desm., Isid. Geoffe, 1, 1. PI, 25. Compare 



PiCTET Notice sur les Ani. nouv. du Mus. de Geneve, ire Livr. PI. i — 3) ; 



Loncheres antricola, Nelomys antricola Lund, Kongel. DansTce Vidensk. 

 Selshals Afhandl. viii. 1841, PI. 23, &c. Individuals destitute of tail which 

 occur not unfrequently in South America amongst these rodents, the loss 



