74 Proceedings of the Biological Society of Washington. 



Specimens examined. — Eight, all from Middle Celebes: Gimpoe, 2; 

 Goenoeng Lehio, 2; Lake Lindoe, 4. 



Remarks. — This species differs conspicuously from the other member of 

 the chrysocomus group inhabiting the same district (Rattus penitus), and 

 externally resembles very closely Rattus nigellus from northern Middle 

 Celebes. From R. nigellus it is chiefly distinguished by the smaller foot, 

 more sharply bicolored tail ; more slender skull with less inflated braincase ; 

 and smaller teeth. Two specimens out of the eight examined have the tip 

 of the tail for 12 mm. whitish. 



Rattus hellwaldii localis, subsp. nov. 



Type from Laboea Sore (north of Parigi), Celebes. No. 218,120, U. S. 

 National Museum; skin and skull of adult cf (teeth moderately worn); 

 collected December 1, 1916, by H. C. Raven; original number 2987. 



Diagnosis. — Like typical Rattus hellwaldii (Jentink) of Menado, North 

 Celebes, but much lighter, less richly colored; pelage shorter and harsher, 

 mixed on back with a few spinous hairs. Skull as in true hellwaldii but 

 with larger auditory bullae. 



Measurements. — Type: Head and body, 174; tail, 186; hind foot, 43. 

 Skull of type: Condylobasal length, 41.2; zygomatic breadth, 19.6; inter- 

 orbital breadth, 7.2; mastoid breadth, 16.5; mandible, 23.5; maxillary 

 tooth row (alveoli), 7.0; mandibular tooth row (alveoli), 7.4. 



Specimens examined. — Twelve from the type locality and one from 

 Parigi. 



Remarks. — In a series of more than 60 specimens of typical Rattus hell- 

 waldii from extreme northeastern Celebes, all of the skins are intensely 

 colored. The specimens in the series from Laboea Sore differ conspicu- 

 ously in their dull, paler coloration. No spiny hairs are apparent in any 

 specimens of typical hellwaldii, but they are present in small proportion in 

 all examples of the new race. A large series of specimens of this group from 

 the interior of Middle Celebes seems inseparable from the typical form from 

 Menado. In many individuals from this region the auditory bullae are 

 abnormally swollen, a condition accompanied by the presence of a nema- 

 tode parasite within the bullae. Such distortion is not present in skulls 

 from other parts of Celebes, nor do we recall its occurrence in any other 

 rats. 



Rattus hellwaldii cereus, subsp. nov. 



Type from Toli Toli, northwestern Celebes. No. 200,232, U. S. National 

 Museum; skin and skull of adult cf (teeth moderately worn); collected 

 November 30, 1914, by H. C. Raven; original nimiber 1846. 



Diagnosis. — Like Rattus hellwaldii hellwaldii, but larger, with longer 

 hind foot; and less richly colored. Skull larger, with larger auditory 

 bulhe. 



Measurements. — Type: Head and body, 200; tail, 181; hind foot, 46. 

 Skull of type: Condylobasal length, 43.2; zygomatic breadth, 20.6; inter- 



