CONTENTS OF VOL. VI. 



A GENERAL NOTICE OF THE BIOLOGICAL MEMOIRS . . . (p. vii.) 



SYNOPSIS UK THE CONTENTS OF THE SEVERAL VOLUMES OF MEMOIRS. . (p. xi.) 

 CLASSIFIED SUMMARY OF THE CONTENTS OF VOLS. I-VI . . (p. xiii.) 



ECHINODERMA. 



III. ON A COLLECTION OF YOUNG HOLOTHURIOIDS. By PROF. E. W. 



MACBRIDE, D.Sc., LL.D., F.RS (9 pp., 2 Pis.) 



POLYCILffiTA. 



By E. EHLERS, PROFESSOR IN GOTTINGEN . . (32 pp., 3 Pis.) 



FRESHWATER ALG^E. 

 By F. E. FRITSCH, D.Sc., PH.D., F.L.S. . . (GO pp., 3 Pis.) 



