NO. 1684. MAMMALt^ OF THE RIIIO-LINOA ARCHIPELAGO— LYON. 485 



Measurements. — External: Head and body, 195 mm, (245) «; tail, 

 230 (255) ; hind foot with claws, 45 (47.5). Cranial: Greatest length 

 of skull, 46.8 (52.7) ; length of nasals in middle line, 17.9 (20.5) ; 

 basal length, 41 (47) ; zygomatic width, 23.5 (2G.2) ; width of ros- 

 trum at antorbital foramen, 8.5 (10.3) ; width of brain case above 

 roots of zygomata, 19 (21.2) ; least depth of rostrum, 8.7 (10.3) ; 

 maxillary tooth row (alveoli), 8.2 (10). 



Specimens examined. — One, the type. 



Remarks. — Although the rats of the Miis p^mAis group hitherto 

 known from the various islands of the Rhio-Linga Archipelago are 

 referable to typical firmus (type-locality, Linga Island), the single 

 known rat of this group from Pulo Jombol appears too different to 

 be regarded as belonging to the same species as the others. That its 

 small size is not due to immaturity is shown by a considerable amount 

 of wear of the teeth, the closure of skull sutures, which remain open 

 in young animals, and the perfect development of angles and ridges 

 on the skull. An examination of many skulls of Mus firmus from 

 the i-slands of the Ehio-Linga Archipelago fails to show any that 

 approach the skull of M. ehomboUs in its general small size, short 

 rostrum, and smaller teeth. The somewhat darker color of M. rhom- 

 holis can not be considered as characteristic, and externally, aside 

 from its smaller size, it can scarcely be differentiated from M. firmus. 



External and cranial 'measurements of rats. 



" Collector's measurements. 



AONYX CINEREA (Illiger). 



1815. Lutra cinerea Illiger, "Abh. Akad. Berlin, 1811, p. 99, 1815." (Type- 

 locality near Batavia, Java.) 



Skin and skull of an adult female. Cat. No. 144434, U.S.N.M., from 

 Pulo Setoko. The size of the teeth in the specimens of clawless 



<» Measurements in parentlieses are those of the type of Mus firmus. 



