188 MURID.E.- — ACOMYS. 



The Cayenne Ecuimys. Echimys cayennensis. 



Pictet, Mem. de la Soc. de Phys. et d'llist. Nat. de Geneve, ix. p. 145. 

 pis. 1-3, pi. 4 (skeleton), 1841-2. — Waterhouse, Nat. Hist. Mamm. 

 ii. p. 334. pi. 10. figs. 6 & 6 a (molar teeth). 



*a. Skull. 



Echimys fuliginosus. 



*a, *b. Skulls. Bahia. Presented by F. de Castelnau, Esq. 



The White-spined Echimys. Echimys alhispinosus. 

 Is. Geoff., Guer. Mag-, de Zool. 1840, pi. 29. figs. 1-3 (molar teeth). 



The Spineless Echimys. Echimys inermis. 

 Waterhouse, Nat. Hist. Mamm. ii. pp. 349 & 498. pi. 16. fig. 5. 



*a. Skull. Bolivia. From Mr. Bridges' Collection. — The specimen 



figured by Mr. Waterhouse. 

 b. Skull : young. 



The Strong-spined Echimys. Echimys hispidus. 



7s. Geoff., Guer. Mag. de Zool. 1840, Mamm. pp. 9, 35 & 54. pi. 29. 

 figs. 4, 5, 6 (molar teeth). 



DACTYLOMYS. 



Teeth :— Incisors ^ ; Molars ^; =20. 



1-1 4—4 



The Typical Dactylomys. Dactylomys typus. 



Guer., Mag. de Zool. 1840, Mamm. pp. 29 & 47. pi. 28. figs. 1-3 



(molar teeth). — Waterhouse, Nat. Hist. Mamm. ii. p. 311. pi. 16. 



fig. 3 (skull, copied). — Deville. Rev. et Mag. de Zool. iv. p. 353. 



pi. 16. figs. 1, 2 (teeth), 1852. ' 

 Echimys dactylinus, F. Cuv., Nouv. Ann. du Mus. i. p. 450. pi. 18. 



fig. 3 (teeth), pi. 19. figs. 5, 6 (skull) ; Dents des Mamm. p. 186. 



no. 73 (dentition), 1825. 

 Dactylomys, Schreb., Saugtk. iv. pi. 239. fig. 10 (dentition). 



ACOMYS. 

 Teeth : — Incisors ^ ; Molars — ; = 16. 



The Egyptian Acomys. Acomys dimidiatus. 

 *a. Skull. Egypt. From the Stockholm Museum. 



Acomys mexicanus. 

 Brandt, M6m. Acad. St. Petersb. vii. taf. 5 a. figs. 11, 12 (dentition). 



