614 MONOGRAPHS OF NORTH AMERICAN RODENTIA. 
on the outer side, a fine ridge, which marks off a secondary groove within the 
first. The same thing occurs in the single-grooved species—castanops, mezi- 
canus, and hispidus. But this carination of the main groove is not always 
perceptible, and is generally so fine as to be liable to be overlooked. When 
most strongly marked, this supplementary groove is just like the inner marginal 
groove itself; and each tooth then seems to consist of two similar halves. 
TABLE I.—Measurements of forty specimens, fresh and alcoholic, of GEOMYS BURSARIUS. 
re From tip of nose to— 2 Length of— E P 
3 3 =e 3 
g Locality. ; as 3 pe gz iS 
3 Bi Se et leenleae aaa 
E wll a ee fee et | ea es 3 
is) a |a}]A}] oO} 8 |e & || a wi. 
eee 1.40 | 1.90 | 6.75 | 2.50 | 1.50 | 1.95 Alcoholic. 
7327 1.65 | 2.00 | 6.50 | 3.00 | 1.50 | 1.35 weados 
1384 5 Uy (Uh ee a = 2.15 | 1.55 | 1.30 .--- do. 
2539 2.10 | 2.33 | 890} 3.30 |...... 1.45 Fresh. 
357 || Saintioule Mo: .-.-c2 <csceroecmes=soces esos || Oyen seteeaeteeceel aee 8.00 | 3.00 | 1.60 | 1.35 ioedas 
2635 |.. 1,75 | 2.20 | 7.00 | 275 | 1.50 | 1.35 Alcoholic. 
2636 1.25 | 2.60 | 7.50 | 3.35 | 1.55 | 1.35 _...do. 
2633 | Illinois... 1.45 | 1.90 | 5.75 | 2.65 | 1.50 | 1.15 ido: 
1775 | Vermilion River .. Trp) |e Aes SAU) easel eh) abe Fresh. 
2630* . aia i| ees | Paeoes 1.75 | 1.20 | 1.05 Alcoholic, 
It o& | 1.17 | 2.08 | 2.42 | 9.00 | 3.08 |..-.-.|-.---- Fresh. 
2 Bt | 1589.) 2048) |) 25457800) |ceanc | een ee| een .---do. 
3 og | 1.12 | 1.94 | 2.62 | 9.00 | 3.07 | 1.80 | 1.37 ieifdos 
4 Q | 0.98 | 1.51 | 2.05 | 7.90 | 2.60 | 1.60 | 1.27 ..--do. 
5 Q | 1.00 | 1.61 | 2.00 | 7.20 | 2.60 | 1.47 | 1.05 potedor 
6 og | 1.10 | 1.95 | 2.36 | 8.50 | 2.96 | 1.66 | 1.35 geeedos 
7 os | 0.94 | 1.60 | 2.08 | 6.50 | 2.57 | 1.50 | 1.20 feo-doy 
8 o | 1.09 | 1.73 | 2.12 | 8.50 | 2.62 | 1.64 | 1.27 Leaedde 
9 so | 1.25 | 1.84 | 2.45 | 9,95 | 3.13 | 1.70 | 1.30 --.do. 
10 Q | 0.94 | 1.46 | 2.05 | 7.50 | 2.48 | 1.60 | 1.18 .-.do, 
11 Q | 0.91 | 1.46 | 1.97} 7.00 | 2.45 | 1.46 | 1.14 ...do. 
12 Q | 0.95 | 1.47 | 1.97] 7.30} 2.50] 1.55 | 1.22 Ussidos 
13 Q | 0.90 | 1.55 | 1.97] 7.45 | 2.72 | 1.60 | 1.27 --.do. 
14 |. og | 1.10 | 1.71 | 2.20] 9.00 | 265 | 1.82 | 1.35 ..-do. 
15 go | 1.23 | 2.15 | 2.47] 9.25 | 3.05 | 1.78 | 1.40 .-.do. 
16 Q | 0.86 | 1.57 | 2.00] 8.00 | 2.76 | 1.63 | 1.35 .--do. 
17 |. 9 | 0.81 | 1.53 | 2.03] 8.00 | 2.61 | 1.60 | 1.27 -.do. 
18 |. o& | 1.05] 1.81 | 230] 9.25 | 277] 1.85 | 1.45 ...do. 
19 g | 0.95] 1.56 | 2.00 | 8.CO | 2.67 | 1.68 | 1.27 .-.do. 
21 og | 0.93] 1.71 | 202] 825 | 3.00 | 1.69 | 1.38 .- do. 
22 Q | 0.83 | 1.50 | 1.90] 7.50 | 2.83 } 1.57 | 1.18 .-.do. 
24 og | 1.15] 1.99 | 2.50] 9.00 | 3.11 | 1.76 | 1.43 _..do. 
25 Q | 1.02] 1.62 | 2.20] 7.85 | 2.77 | 1.68 | 1.33 ...do. 
26 2 | 0.93 | 1.54 | 2.12 | 7.12 | 2.67 | 1.55 | 1.28 .-.do, 
BL Q | 0.62 | 1.15 | 1.63 | 6.00 | 2.25 | 1.37 | 1.14 ---do. 
32 So | 0.71 | 1.25 | 1.62 | 6.50 | 2.68 | 1.55 | 1.25 Feit 
33 Q | 0.91 | 1.47 | 2.00 | 825 | 2.66 | 1.65 | 1.23 ---do, 
38 Q | 0.96 | 1.55 | 1.92] 7.00 | 2.92 | 1.64 | 1.25 .--do. 
40 |. o | 0.77] 1.19 | 2.10 | 6.08 | 2.55 | 1.55 | 1.26 .- do. 
42 os | 1.09 | 1.54 | 2.20 | 8.50 | 3.03 | 1.62 | 1.37 ...do. 
* A type of breviceps. 7 
+ Nos. 1-42 (orig. nos.) were measured in the flesh by the collector, Dr. C. E. McChesney, U.S. A., whose care in this 
matter greatly increased the value of an important collection of Mammals made by him in the locality named. “‘ Fort Sis- 
seton” was formerly Fort Wadsworth, Dakota, 
