CLARKE, H. J. ’78. Lucernariæ and their Allies. Washington: Smithsonian Institution. CLAUS, C. ’78. Ueber Charybdea marsupialis. Arb. aus d. Zool. Inst. d. Univ. Wien, Band II, Heft 2. DOFLEIN, F. ’96. Die Eibildung bei Tubularia. Zeitsch. f. wiss. Zool., Bd. LXII, Heft 1. HAECKEL, E. ’79. Das System der Medusen. Jena.--’81. Challenger Report on the Deep-sea Medusæ. Vol. IV. HERTWIG, O. and R. ’78. Das Nervensystem und die Sinnesorgane der Medusen. Leipzig. HESSE, R. ’95. Ueber das Nervensystem und die Sinnesorgane von Rhizostoma Cuvieri. Zeitschr. f. wiss. Zool., Bd. LX, Heft 3. MÜLLER, F. ’59. Zwei neue Quallen von St. Catherina (Brasilien). Abhandlungen der naturf. Gesellschaft zu Halle. SCHEWIAKOFF, W. ’89. Beiträge zur Kenntniss des Acalephenauges. Morph. Jahrb., Bd. XV, Heft 1. WILSON, H. V. Unpublished notes. TABLE OF REFERENCE LETTERS. _afr_ = adradial furrow. _afr´_ = furrow in Tripedalia that separates perradial from interrad. regions in lower half of bell. (In Charybdea the same furrow is directly continuous with _afr_.) _ax_ = axis of nerve. _c_ = concretion. _cc_ = canal underneath _ivl_, connecting the two adjacent marginal pockets. _ccl_ = circular canal. _ci_ = cilia. _cm_ = circular muscle. _co_ = cornea. _cp_ = capsule of lens. _cs_ = covering scale of niche. _csc_ = canal of sensory club. _ct_ = canal of tentacle. _ct´_ = beginning of canals of lateral tentacles in Tripedalia. _ec_ = ectoderm. _ece_ = ectoderm of exumbrella. _ecs_ = ectoderm of subumbrella. _ed_ = distal paired eye. _el_ = larger unpaired eye. _en_ = endoderm. _enc_ = endoderm of sensory club. _enf_ = tract of nerve fibres underlying endoderm. _enfl_ = endoderm of floor of stomach. _enp_ = endoderm of stomach pockets. _enr_ = endoderm of roof of stomach. _ens_ = endoderm of stomach. _ep_ = proximal paired eye. _es_ = smaller unpaired eye. _fc_ = funnel leading into canal of sensory clubs. _fp_ = fibre from subepithelial plexus of subumbrella. _fph_ = filaments of phacellus. _frn_ = frenulum. _ft_ = funnel-shaped depression in ectoderm axial to base of tentacle. _g_ = gelatine. _gc_ = ganglion cell. _ge_ = gelatine of exumbrella. _go_ = gastric ostium. _gs_ = gelatine of subumbrella. _hvl_ = horizontal vascular lamella. _i_ = interradius. _if_ = interradial funnel of bell cavity. _ifr_ = interradial furrow. _ivl_ = interradial vascular lamella. _l_ = lens. _lv_ = lip of valve. _m_ = bell margin. _mc_ = mucous cell. _mep_ = mesogonial pocket. _mo_ = mouth. _mp_ = marginal pocket.