Scyphozoa 143 



Rotijera. Philodina is easily cultured by either the method of 

 Stylonychia [See p. 64.] or of Paramecium. [See p. 63.] 



Entomostraca. Cyclops, Canthocamptus, Diaptomus, Cypris, and 

 Daphnia have been cultured with moderate success by the following 

 method. Two grams of egg yolk, ground into a paste, are added to a 

 gallon jar filled with green pond or aquarium water. This is allowed 

 to stand for about three days and then inoculated with small Protozoa 

 (any species not larger than Colpoda). Next the organism to be cul- 

 tured is introduced — for Cyclops, Canthocamptus, and Diaptomus a few 

 males and egg-bearing females will suffice, but for Daphnia and Cypris, 

 as many individuals as possible are added. Within a month successful 

 cultures will show organisms in abundance, a condition which will last 

 some 6 weeks.* 



Annelida. Microdrilli, such as Nais, Aelosoma, and Dero have re- 

 sponded splendidly to culture in 30 cc. of Solution A (see footnote on 

 p. 73) added to rice-agar as in the case of Amoeba [see p. 72]. The 

 medium in this case, however, should stand for three days before in- 

 oculating with the annelids (about 5 will suffice). The number of these 

 organisms can be increased by using larger vessels, i.e., allowing for more 

 fluid and increasing the surface area of the agar. 



Class Scyphozoa 



REARING THE SCYPHISTOMA OF AURELIA IN THE 



LABORATORY** 



F. G. Gilchrist, Pomona College 



THE scyphistoma of Aurelia proves to be a very hardy marine form; 

 it may be maintained alive and in fairly active state of budding by 

 keeping it in shallow dishes of sea water (it is well to have the sea- 

 water slightly hypotonic) and feeding with ground shrimp or particles 

 of meat. Of course the water should be changed after feeding. The 

 scyphistoma does best with a mixed diet. Scyphistomas have been 

 reared at marine laboratories, using plankton tow (Delap, 1905, 1907) 

 or sea urchin ovaries (Herouard, 1909). 



Bibliography 



Delap. 1905. Rep. of Sea and Inland Fisheries of Ireland for 1902 and 1903. 



■ 1907. Ibid, for 1905. 



Herouard. 1909. C. R. Acad. Sci. Paris, p. 148. 



♦For Daphnia, the cultures require a temperature of 17-19 C. This was obtained by 

 circulating cold water through a coil of glass tubing (6-8 mm.), set within the gallon jar. 



** Editor's Note: For a more complete description of the methods of rearing Aurelia 

 aurita and other medusae see Hagmeier, A.: Die Zuchtung verschiedener wirbelloser Mee- 

 restiere. In Abderhalden, 192 7-1933: Handbuch der Biologischen Arbeitsmethoden Abt. 

 9, Teil 5:553-562. P. S. G. 



