No. 514] 



NOTES AND LITERATURE 



as the last word, but of course not as the final adjustment, which 

 must come slowly, as new material is gathered from the lesser 

 known areas of the range of the genus, especially from the region 

 south of the United States. 



His paper is accompanied by a key to the species, and also by 

 keys to the subspecies where such are required. A colored map 

 shows the distribution of the species and subspecies of the /Yro- 

 myscus maniculatus group, with indication of the intergrading 

 areas between the recognized forms. The twelve text figures con- 

 sist of small maps showing the range of all of the other species 

 and subspecies. There are also tables giving the average and 

 extreme external and cranial measurements of series of speci- 

 mens of each form. Seven of the eight plates illustrate the 

 skulls of some fifty or more species and subspecies (from photo- 

 graphs), while plate eight gives enlarged figures of the teeth and 

 soles of the several subgenera. 



It is to be regretted that the biblinuTapbical references are 

 restricted to the citation of synonyms, and thus fail to give clues 

 to the work of previous authors, so essential to subsequent inves- 

 tigators in following up the history of a species or group, and 

 hence of high importance in monographic treatises like the pres- 

 ent. Aside from the convenience such references afford, they are 

 important as a means of coordinating, definitely, from the mono- 

 grapher's standpoint, the work of previous authors. Further- 

 more, in the lists of "specimens examined," only the localities 

 and number of specimens from each are mentioned, the name of 

 the collector and the collection where the specimens are located 

 being omitted, thus giving no clue to the particular specimens to 

 which the monographer refers. This, however, is obviously due 

 to a faulty system of treatment rather than to the preference of 

 the author, since the same method characterizes the long list of 

 important monographs issued under the auspices of the Biolog- 

 ical Survey. The addition of these essential items of informa- 

 tion would considerably increase the amount of text, and for this 

 reason have perhaps been omitted, since it is known that, for a 

 long time at least, the restriction placed by the officials "higher 

 up" in the Department of Agriculture on the technical publica- 

 tions of the Biological Survey were practically prohibitive of 

 monographic papers exceeding a certain number of pages. 



J. A. Allen. 



