202 Phylum Annelida 



Macrobdella decora in perfectly good condition without food for as long 

 as 14 months. Most of them require little space and they are resistant 

 to a wide range of temperatures, especially at the lower ordinary registers. 

 But cleanliness is requisite as most species soon succumb to foul or over- 

 heated water. They are also extremely sensitive to many mineral and 

 organic poisons and even minute traces of copper sulphate, calcium 

 chloride, chloroform, nicotine, etc., may be quickly fatal if the leeches 

 cannot escape. 



The fish leeches (Ichthyobdellidae) are mostly marine and have been 

 little cultured. Some of them have been kept in the aquaria at Naples 

 and Plymouth where their natural hosts are available. The freshwater 

 Piscicola and related genera may be kept in aquaria, either balanced or 

 with running water, with sunfish, goldfish, or other small fishes as hosts. 

 They will attach their egg capsules to aquatic plants, to stones, or to the 

 glass. They are sometimes exceedingly numerous and harmful in the 

 artificial ponds and tanks of trout and other fish hatcheries. 



But most useful are the common species of Glossiphonidae. The 

 smaller species may be kept indefinitely, preferably in a moderately cool 

 and light place out of direct sunlight, in finger bowls or small crystallizing 

 dishes, with a few sprigs of Elodea or similar aquatic plants. A few 

 living water snails, such as Physa or Lymnaea, should be added from 

 time to time for food. Pond or spring water should be used, as tap 

 water is frequently chlorinated or otherwise treated and as a consequence 

 is likely to be injurious. Any dead or dying leeches or snails and their 

 feces should be removed promptly. The water should be changed if it 

 shows any indications of contamination. This is easily done as the leeches 

 usually cling firmly to the sides of the vessel. If, in order to stimulate 

 the growth of the plants, it is desired to place the dishes at a window ad- 

 mitting some sunlight, a few pieces of shale, clam shell, or dead leaves 

 should be added to afford concealment and protection. Twenty or thirty 

 of such small species as Helobdella stagnalis or H. lineata (jusca) or half 

 as many Glossiphonia complanata will thrive in a finger bowl, exchange 

 spermatophores and produce fertile eggs in abundance throughout spring 

 and summer. The young are easily raised but care should be taken to 

 avoid overcrowding or undue disturbance as they often die if detached 

 from the mother before most of the yolk is absorbed. After the young 

 become free it is best to remove them to a separate dish. Should it be 

 desired to keep large numbers of these leeches, small balanced aquaria 

 with a bottom layer of sandy soil and with plants with ensheathing leaf 

 stalks, like Sagittaria, in addition to Elodea or Myriophyllum, and a 

 supply of snails will serve admirably. 



The larger glossiphonids (Placobdella parasitica, P. rugosa, P. multi- 

 lineata, P. montijera, etc.) may be kept indefinitely in finger bowls or 



