NO. 1101. PROCEEDINGS OF THE NATIONAL MUSEUM. 31 



To sum up this discussion regarding size, it may be stated that Sealops 

 aquaticus is largest in the northwestern portion of its range and some- 

 what smaller in the middle Atlantic States, in New York and Pennsyl- 

 vania. From thence southward it gradually diminishes in size, reaching- 

 the extreme in Florida. Alon^; the Gulf coast there is a slight increase, 

 which is lost again in Texas, where the average is practically the same 

 as in Florida. As the Gulf coast is departed from, there is a gradual 

 increase in size, which becomes a sudden one about on the thirty-sixth 

 parallel. Il^orthward the species maintains a maximum size over a wide 

 area. 



This discussion of size has purposely been based on the size of the 

 skull, but the size of the whole body furnishes similar indications of 

 average increase and decrease. It is more difBcult to determine how 

 far these are illusive in the latter case, on account of the differences in 

 the measurements of fresh specimens, made by different collectors, and 

 the changes produced by the immersion of specimens in alcohol. 



As regards color, the Kew York specimens are perhaps the darkest 

 of the series before me. There is a moderate increase in jjallor south- 

 ward along the Atlantic Coast, but it is far from being pronounced. 

 Specimens from Ohio, Illinois, and the northern Mississippi Valley 

 generally are not perceptibly lighter in color than those from New 

 York. Hence, the name argentatus or silvery, as applied to western 

 ScalopH generally, is misleading. The only quite light-colored speci- 

 mens from this region, which I have examined, are two from Elk Eiver, 

 Minnesota, one from Council Bluffs, Iowa, and one from Camp Douglas, 

 Wisconsin. The Minnesota specimens are distinctly silvery, and merit 

 the name argentatus much more than specimens from the locality of 

 the type in Ohio ; and this is true in a still greater degree of the Wis- 

 consin specimen. In southern Kansas the color is relatively light, and 

 from thence southward into Oklahoma and central Texas there is a 

 strong increase in pallor, which reaches its culmination in Padre 

 Island, Texas, and the vicinity, where the surface color is sometimes a 

 silvery white. 



The peculiar orange-red coloration on the heads, wrists, and other 

 parts of some specimens, especially those from the Southwest, will be 

 considered in connection with the discussion of the subspecies which 

 have been proposed, as this i3eculiarity has been mentioned in the 

 diagnoses. 



DISCUSSION OF THE NOMINAL SPECIES AND SUBSPECIES. 



Among the important nominal species which I have assembled under 

 the name of 8. aquaticus^ is the Talpa machrina of Kafiuesque, described 

 in 1832 from specimens from near Lexington, Kentucky. His account 

 of it leaves no doubt that it is the mole of the Mississippi Valley, 

 which has hitherto been recognized under the later name of argentatus. 

 He described at the same time another Kentucky mole, under the name 



