MARINE AQUARIA 



brackish water, preferably on a muddy bottom; and is abundant in calm 

 weather in pools and ditches among vegetation, and about piles and other 

 submerged woodwork. It is a very good aquarium scavenger; also serv- 

 ing as food for the fishes and other inmates. 



Pandalus borealis, (Kroyer), or Deep Water Prawn, is a 6 to 7 inch 

 long species which never approaches the shore. Two other forms, P. 

 montagni and P. prepinquus, also inhabit deep water having abundant vege- 

 tation. 



Ctrripedia. These Crustaceans include the Barnacles and similar 

 forms everywhere plentiful in salt and brackish water. A few of the larger 

 forms attached to a plant or stone may be introduced into the aquarium, 

 but should be under careful observation, as they do not usually survive. 

 The most common are Balanus eburneus, or Black Barnacle, Sea-acorn ; 

 B. balanoides, or Ivory Barnacle, common on the Atlantic coast on most 

 submerged woodwork, either fixed or floating, and B. crenatus, a parasitic 

 form attached to crabshells, stones, etc. The larger B. tintinabulum, and 

 Lepas fascicularis, or Goose Barnacle, are found attached to the bottoms 

 of vessels that have come from warmer latitudes. 



Marine Entomostraca. The order Crustacea also includes those 

 of minute size, Water-fleas which are both free-swimming and parasitic. 

 They form a considerable part of the food of fishes and other marine an- 

 imals and need no further mention here. 



Amphipoda. These forms are numerous on all beaches; the most 

 generally distributed are: 



Orchestia agilis, (Smith), or Beach Flea, Sand Hopper, which occurs 

 in countless numbers on every beach. When disturbed it hops by means 

 of the three pairs of abdominal legs and buries itself in the sand. In color 

 it resembles the sandy shore, and is S/^ inch and less in length. Another 

 form Talorchestia lingiconis, is similar to the above. 



Gammarus locusta, (Lat.), also resembles the above but is larger and 

 lives in the water under stones and among the weeds. The colors are 

 uncertain and variable. 



Caprella geometrica, (Lat.), or Skeleton Shrimp, is a small and curi- 

 ous amphipod, so slender as to appear like a skeleton adhering to the 

 seaweeds. It is about f^ inch long and moves like a measuring- worm. 

 Will survive in the aquarium. 



There are a number of Boring Amphipods which do not require 

 mention here. 



IsopoDA. This numerous class is widely distributed and is frequently 

 found on marine plants. The most general form is : 



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