1902.] AND ANCIENT GEOGRAPHY. 281 



Taking together the distribution of the five groups, we find that 

 the range of the genus Cambarus extends over the following parts 

 of North America : In Mexico, the respective species are reported 

 from the following States : Vera Cruz (near Vera Cruz and 

 Orizaba), Pueblo, Mexico, Michoacan. This line would represent 

 the southern boundary of the range.^ Further, the genus has been 

 found in the States of Jalisco and Sinaloa (Mazatlan) (in the drain- 

 age of the Pacific Ocean) ; on the central pleateau, in Guanajuato, 

 San Luis Potosi (Santa Maria) and Coahuila (Parras). This latter 

 locality forms in a certain degree the connection of the Mexican 

 part of the range of the genus with that of the United States, since 

 the Mexican State Coahuila extends northward to the Rio Grande 

 del Norte, and just across this river, on its left bank, there is, in 

 Kinney county, Texas, a locality for C. clarki. Thence the range 

 of the genus is apparently continuous, and reaches eastward to the 

 sea (Gulf of Mexico and Atlantic Ocean).* Toward the west and 

 north it is circumscribed by the following line : from Kinney 

 county, Texas, to New Mexico (including its eastern part), then 

 receding toward Indian Territory and leaving out Oklahoma, 

 farther, including Kansas, the southeastern corner of Wyoming 

 Tpossibly a part of Colorado), the southern and eastern part of 

 Nebraska, crossing here the Missouri, including Iowa and Minne- 

 sota and possibly parts of the Dakotas, at any rate the northeastern 

 corner of North Dakota, crossing over into Canadian territory and 

 including the region of Lake Winnipeg and Saskatchewan river 

 (northernmost point). Thence this line recedes in a southeasterly 

 direction, reaches Lake Superior, and follows the Great Lakes as far 

 as Lake Erie. At Lake Ontario it advances again northward and 

 follows at a certain distance the St. Lawrence river, reaching at the 

 Lake St. John in Quebec the northernmost point in the East. 

 Then it turns southward, crosses the St. Lawrence and includes, in 

 New Brunswick, the drainage of the Restigouche and Miramichi 

 rivers (emptying in the St. Lawrence Gulf) and also the St. John 

 river (emptying in the Bay of Fundy). Thus the largest part of 

 New Brunswick seems to belong to the range of this genus, while 



^ The genus is said to be represented near Alta Vera Paz, in Guatemala (Faxon, 

 1885, p. 173). This would advance the range southward beyond the Isthmus of 

 Tehuantepec. This locality, however, needs confirmation. 



2 In Florida, only in the northern half are localities known, southward as far as 

 Orange, Lake and Hillsboro counties. 



