Hirudinea 201 



be quite small and should be one which will stay in suspension. 



6. Each day, and this is most important, the bowls should be care- 

 fully inspected to note: 



a. Are the larvae quite active? 



b. Are they feeding? 



c. Is the diatom culture well under control by the feeding larvae? 

 Perhaps nothing will insure failure more surely than feeding too much 

 diatom culture, or allowing the culture to reproduce in the finger bowls. 

 A sufficient amount of it should be fed once each day so that upon in- 

 spection the following day at feeding time practically all has been used 

 by the larvae as food. 



7. If there are signs of any fouling, or if the diatoms become too 

 numerous, the larvae should immediately be taken out with a small 

 pipette and transferred to a clean bowl with freshly filtered seawater. 



8. Each day, just after feeding, gently aerate the water in each bowl 

 with three or four pipettefuls of water from the same bowl. Better still, 

 just before feeding carefully remove three or four pipettefuls of water 

 from each bowl, feed the larvae, and then squirt three or four pipettefuls 

 of freshly filtered seawater into each bowl. Either of these methods 

 serves to aerate the water and to distribute the diatoms throughout the 

 water in the bowls. 



Bibliography 



Fisher, W. K., and MacGinitie, G. E. 1928. A New Echiuroid Worm from Cali- 

 fornia. Ann. and Mag. Nat. Hist. 1:199. 

 1928. Natural History of an Echiuroid Worm. Ibid. 1:204. 



Class Hirndi?iea 



LABORATORY CARE OF LEECHES 



J. Percy Moore, University of Pennsylvania 



BESIDES serving for problems peculiarly their own, leeches offer 

 suitable subjects for the study of certain general problems of 

 physiology and behavior and some of them provide beautiful material 

 for embryology, both observational and experimental. For the latter 

 purposes common species of the Glossiphonidae, such as Glossiphonia 

 complanata, Helobdella stagnalis, and Placobdella parasitica, are to be 

 recommended, as the eggs and embryos are carried in large numbers by 

 the female parent either in delicate capsules or uninclosed. 



Except for certain of the fish leeches (Ichthyobdellidae) culture is 

 simple and easy. Many of them will live under almost anerobic con- 

 ditions and the sanguivorous species especially will thrive for a long time 

 on a single meal of blood, or even without feeding at all. I have kept 



