GEOGR VPTTTC VL DISTRIBUTION. 



For the sake of showing more strikingly the character of the dif- 

 ferent Acalephian Faunaa of our coasts, lists have been prepared 

 embracing several species not enumerated in the Catalogue, to give 

 a better idea of the peculiar stamp of the regions into which our coast 

 has been divided. No names arc here given to these faunal divisions, 

 as in a forthcoming number of the Museum Catalogue the limits and 

 nomenclature of our Marine Fauna? will be fully discussed. For the 

 present I shall simply point out in a general manner some of the more 

 interesting points of the distribution of our Acalephs. Several species 

 have a very extensive range ; on the Atlantic side, from Greenland to 

 Long Island Sound, and from Grand Manan to Charleston, South Caro- 

 lina. In the Pacific Ocean we find species which range from Kamt- 

 schatka to the northern part of California. Within these extensive 

 belts there are other species more limited in range, extending only 

 from Massachusetts Bay to Eastport, from Charleston to Cape Cod, 

 from San Francisco to the Gulf of Georgia, or from the Gulf of Georgia 

 to Behring's Straits ; while a third series of species is still more lim- 

 ited, extending only along such portions of the shores as Nova Scotia, 

 Massachusetts Bay, Long Island Sound, the coast of Southern California, 

 the Gulf of Georgia, and the like. 



The areas of distribution of the different species overlap and enclose 

 one another so as to give us for the character of the Fauna of any par- 

 ticular locality three different elements of distribution ; first, the cos- 

 mopolitan species, spreading over wide areas ; next, the species which 

 range over more limited areas ; and finally, the local species scattered 

 in the areas of the limited species. It is the peculiar combination of 

 these three elements which gives to a special locality what has been 

 called its faunal character, but owing to the intricate crossing, overlap- 

 ping, and enclosing of these areas, we find it nearly impossible to draw 

 lines along our coast which should embrace homogeneous elements. 

 Such areas are found on our coast, extending approximately from 

 Greenland to the northern part of Nova Scotia, from Nova Scotia to 

 the northern part of Maine, and from Massachusetts Bay to Cape Cod ; 

 the coast of Long Island Sound and New Jersey, as far as Cape Hat- 



