Ectoprocta 



179 



wooden floats in the region where the species occurs normally. Wooden 

 crosses measuring three or four feet in length have proved excellent for 

 the purpose (Fig. 46). They were tied to a dock and allowed to float on 

 the surface. So constructed they do not turn over in storms and thou- 

 sands of colonies soon appear on their lower surfaces; from these samples 

 may be taken for study from day to day. Sexually mature colonies 

 which liberate great numbers of larvae daily may be grown in this way. 

 Bugnla turrita has the same life history but it grows in somewhat 

 different situations. The larvae show interesting structural differences, 

 especially in the presence of visible pigmented eye spots, but they respond 



Fig. 46. — Type of wooden cross used to grow colonies of Bugula 

 flabellata and other sessile organisms, such as barnacles, as- 

 cidians, and hydroids. (Construction: spruce or pine, 2x4; 

 three feet long with cross bar 1x6, two and one half feet long, 

 sunk flush with the surface.) 



to the same treatment, their behavior being the same in all respects, 

 larvae of B. turrita may be liberated in the afternoon.* 



The 



CULTURING FRESHWATER BRYOZOA 



Mary Rogick, College of New Rochelle 



FRESHWATER Bryozoa are among the most common of aquatic 

 invertebrates. Ponds, rivers, streams, lakes, harbors, bays, and 

 quarries abound with specimens. Bryozoa may readily be collected 

 throughout the spring, summer, and fall in either one or two of the fol- 

 lowing stages: colony, statoblast, or hibernaculum. Hibernacula are pro- 

 duced by colonies of Pottsiella and Paludicella while statoblasts are 

 produced by the Plumatellas, Cristatella, Pectinatella, Lophopodella. 

 Lophopus, and Fredericella. Houghton and Marcus admit the possibil- 

 ity of over-wintering in the case of Fredericella and Lophopus under 

 favorable conditions. 



Collection of Bryozoan forms is simple. Floating statoblasts may be 

 obtained by skimming over the surface of the water with a silken dip-net. 



* A more complete account of the behavior of the larva and the rate of growth of the 

 colony may be found in /. Morph. 49:355, 1930. 



