abstracts: mammalogy 659 



CRYSTALLOGRAPHY. — Modern extensions of Hauy's laws of crys- 

 tallography. Edgar T. Wherry. Amer. MineraL 3: 134-136. 

 1918. 

 It is pointed out that many of the modern developments in crystal- 

 lography represent logical extensions of the laws formulated by Hauy 

 over 125 years ago. E. T. W. 



MAMMALOGY. — The rice rats of North America (Genus Oryzomys), 

 Edward A. Goldman. N. Amer. Fauna 43 : 1-100, pis. 1-6, 

 figs. 1-11. September 23, 1918. 



The genus Oryzomys, of wide distribution in North and South 

 America, has, for the systematist, long been one of the most difficult 

 groups of small mammals; and there has been a considerable difference 

 of opinion as to the status and distribution of the comparatively few 

 forms found in the United States, while the intricate maze of species 

 and subspecies in the Tropics has proved a stumbling block for almost 

 every worker. In every extensive collection many specimens were 

 wrongly determined, or simply stored without an attempt at specific 

 identification. 



In the present revision Major Goldman has recognized 51 forms 

 from Panama northward, 44 of which he places in the typical subgenus 

 Oryzomj^s, 5 in the subgenus Oligoryzomys, and 2 in the subgenus 

 Melanomys. Two Mexican subspecies are described as new: Ory- 

 zomys melanotis colimensis from Armeria, Colima; and Oryzomys fulves- 

 cens mayensis from Apazote, Campeche. The author predicts that 

 when many regions now unexplored are carefully worked by collectors, 

 the forms assignable to Oryzomys will probably far outnumber those 

 of any other genus of American rodents. More than 150 species and 

 subspecies have already been described in the genus, many of these 

 from South America and therefore extralimitary to the present paper. 

 Some forms have in late years been separated from Oryzomys by the 

 erection of closely allied genera, and a careful revision of the South 

 American genera, subgenera, species, and geographical races of Ory- 

 zomys and its allies, somewhat comparable to Goldman's work, would 

 be a boon to mammalogists. The relationships between the genera and 

 subgenera of Oryzomys-like rodents are especially complex and there 

 will doubtless always be a considerable difference of opinion regarding 

 the relative values of the named groups, the various sections blending 

 one into another in an intricate manner. The author calls attention 



