iV 60V 
Vol. XXVII, pp. 57-60 March 20, 1914 
PROCEEDINGS 
OK THK 
BIOLOGICAL SOCIETY OF WASHINGTON 
FOUfl NEW' NEOTROPICAL RODENTS. 
P>Y X. HOLLISTER. 
11’uhlishod liy pi'nnission of tlit' Socrctiiry of tlio Sniitlisoniim Institution.] 
Among the mammals from Middle and South America in 
the collection of the United States National Mnsemn are speci¬ 
mens of four hitherto imdescrihed rodents. 
Proechimys rubellus sj). nov. 
Tijpe front Ango.stnrti Valle^^ (Atsta Rica. Adult [U]; collected by 
.lose G. Zeledoti. IT. S. National iVIuseuin No. tfdrh and skull. 
Characters. — Like Proechhnys centralis and P. c.-chiriquinv.s, but gen¬ 
eral coloration much more reddi.sh, less dnsky, with less mixture of 
grayish- and yellowish-buft' and more bright hazel on cheeks and sides, 
and with little Itlackish suffusion in color of uytiteritarts. Tail shorter. 
Skull as ill Proechimys centralis. 
Measurements of type (from dry skin).—Head and body, '250 mm.; 
tail, 1.30; hind foot, .55. Skull and teeth: (ireatest length of skull, (U.7; 
condylobasal length, 52.:); nasals, 24.3; upper tooth row, alveoli, 9.2; 
mandible, 33d); mandibular tooth row, 9.7. 
Pcemarks. — While Nicaraguan specimens of Proechimys centralis centralis 
and toyiotypes of Proechimys centralis cJiiriquinus scarcely differ from each 
other in color, tlie Angostura Valley skins are sharply ditierentiated from 
each by their bright reddish-brown coloration. The superficial re.sem- 
hlance to Proechimys mincx of Colomhia is pronounced, but the new 
form is even inore redflish in color and has a much shorter tail. Three 
specimens from the type locality are in the collection. 
Myocastor coypus santacruz® subsj). nov. 
Type from north bank of Rio Salado, near Los Ralman's, Santa ('ruz, 
Argentina. Adult [cf'] ; collected by W. Frakes. f. S. National .Mus¬ 
eum (Biological Survey Gollection) i\o. 9()5i:>, skin and skull. 
C/taracfers. —Larger and lighter colored than Myocastor coypus coypus 
of Chile: WkQ Myocastor hoyiariensis (Geolfroy) from the I'arana River, 
but lighter and more reddish brown, the long ovi'rlying hairs less bully, 
10 —Proc. Hioi,. Soc. Wash., Voi.. XXVII, 1914. Cl) 
