ASTACID^E. 103 



Cuba. — One species : C. Cuboms, from the marshes in the central 

 part of Cuba. 



Accordinjf to the list given above, we know nothing upon the geo- 

 graphical distribution or even the existence of species in the following 

 nineteen States and Territories : — 



1. Maine, New Hampshire, Massachusetts, Connecticut, Rhode Island, 

 Delaware, Michigan, Minnesota, Indian Territory, Kansas, Dakota, Wy- 

 oming, Montana, Idaho, Colorado, Utah, Arizona, New Mexico, Nevada. 



2. From nine States and Territories we know one species, the local- 

 ity l)eing definitely known in only one half of them, viz., Vermont, 

 Maryland, District of Columbia, Tennessee, Iowa, Arkansas, Wisconsin, 

 Nebraska, and Washington Territory. 



3. From three States we know two species, viz., Florida, Indiana, 

 California. 



4. From eight States we know three species, viz.. New Jersey, Penn- 

 sylvania, North Carolina, Louisiana, Kentucky, Texas, Oregon. 



5. From Ohio and Mississippi, four species. 



6. From three States we know five species, viz., Virginia, Alabama, 

 Missouri. 



7. From three States we know seven species, viz., New York, Illi- 

 nois, South Carolina. 



8. From one State we know ten species, viz., Georgia. 



The first step to take, and the best way if we would make progress 

 in knowledge, is always to ascertain how limited it is ; and for this pur- 

 pose it is evidently profitable to show that the undoubtedly unrivalled 

 materials before me represent a very limited part of the gigantic terri- 

 tory comprised in the United States. Besides more than the western 

 half, noticed before as not represented in our catalogue, it is surprising 

 that the much-explored New England States are nearly wanting. Per- 

 haps the multitude of manufactories and the consequent spoiling of the 

 water, especially of the running streams, has some influence on the rar- 

 it}' of the fresh-water crabs ; but a more careful exploration is doubt- 

 less necessai-y to prove the existence or the absence of Astuckkc. 



At the same time some of the other States, seemingly better repre- 

 sented in our catalogue, are fiir from being well explored ; even some, 

 furnishing the largest number of species, are in reality to a great ex- 

 tent unexplored. 



Of the great State of New York we are only acquainted with the 

 eastern border, and in New Jersey with a single locality in the vicinity 

 of New York City. In Maryland and the two Carolinas we know only 

 a small area, along the eastern limits. In Florida, Alabama, and Louisi- 

 ana, only the localities very near to each other are noticed, while all 

 the rest of these States are unexplored. The number of species in 



