132 Mr. C. S. Harris on the Marine Vivarium. 



it. At first I put into the tank (a long glass case, length 2~ ft., 

 depth 18 inches, width 12 in. ; the bottom of 3-inch mahogany, 

 with a gutta-percha tap to draw off the water) all the curious ob- 

 jects that presented themselves in my dredging, and for some 

 time derived much pleasure in watching them ; but I soon found 

 that crowding was not onl}'^ injurious to the various tribes, but 

 that it caused the water to become foul. 



The Actinia dianthus, A.parasitica, A.crassicornis, I have found 

 the longest lived ; dianthus I have 3J^ years old, and some 2 years 

 old, born in the tank : this species I have never yet found take 

 any food I offered, therefore I suppose it derives its nourishment 

 from animalculse ; it is the best for keeping and the most beau- 

 tiful, standing up some 6 to 9 inches ; the others I occasionally 

 fed with a portion of mussel, previously washed, to destroy the 

 milky substance that would foul the water. With these live very 

 well the small Hermit Crabs and Swimmers (crabs), also the 

 Rock Blennies ; the latter I have had tame enough to come to 

 the surface and feed from the hand ; I kept them five months, 

 when they were destroyed by my crowding in too many things, 

 with the desire to show a friend. I have found it adnsable to 

 clean all the Actinia previous to placing them in the tank, by 

 keeping them in a tub of salt water, and taking off the dirt and 

 slime with a soft brush ; they will then throw out a quan- 

 tity of milky liquor, which, if in the vivarium, would foul it. As 

 a rule, I clean everything and keep it apart for a few hours 

 to get purged, fish excepted. All the Pectens are amusing, 

 and tolerably long-lived. The Goby is a long liver also. The 

 SertularicB are beautiful objects. Tubularia gracilis, T. indivisa, 

 Lucernaria auricula, L. campanulata, are all beautiful, and when 

 near the glass and viewed with a lens, highly interesting ; they do 

 not foul the water if taken out when dead. All the above have been 

 in one tank, the water of which in winter was changed once in 

 two or three weeks, in summer twice a week. Growing on pieces of 

 rock were Irid(za edulis, Entcromorpha erecta, and E. intestinalis ; 

 these all kept well. I was much troubled with a green weed, 

 wbich during the summer months covered everything, and could 

 only be kept down by a thorough cleaning every week ; but in one 

 experiment I made with some water left a whole summer in a 

 globe, this green weed (I think an Entcromorpha) kept the water 

 perfectly sweet : this globe was placed out of the influence of the 

 sun, but open to the rain. Another beautiful object, but which, 

 unless the water is frequently changed, continues in beauty but a 

 few days, is the Alcijonium digitatum ; nothing can be more beauti- 

 ful when fully distended. I have kept them eight to ten days by 

 frequent changes of water, as they are apt to turn it milky, which 

 is certain destruction to all in the tank ; they are very abun- 



