sets of appendages, also of unequal size, which are the nutritive organs of the community. They are clustered together on a stem like the others. The appendages of the third kind are small, resemble bunches of grapes, and are scattered among the nutritive hydræ. These last are the reproductive zoöids of the community. GENUS ^Vellela^ ^V. limbosa.^ This hydroid is abundant on the Florida coast. It has a bright-blue, flattened, oblong, bladder-like float, four to five inches [pg132] long, which, is divided into a number of concentric, communicating compartments. The margin of the float is entire, and a triangular sail extends diagonally across the top. On the under side is a single mouth on a manubrium, and surrounding it are a large number of short thread-like appendages having different functions. Some of them are feelers, others bear reproductive buds, and others have stinging-cells. Associated with /Vellela/ is an allied hydroid called /Porpita/, which has no sail, and in company with these two is a jellyfish called /Rataria/, which is supposed to be the offspring of one or the other of them. [Illustration: /Vellela limbosa./] TABLE SHOWING THE CLASSIFICATION OF THE SCYPHOZOA DESCRIBED IN THIS CHAPTER Class =SCYPHOZOA= (/Velum usually absent and tentaculocysts present; the eggs are discharged into a gastric cavity. The type of this class is Aurelia/) Order =STAUROMEDUSÆ= (/Umbrella conical or vase-shaped; no tentaculocysts/) Genera Species ^Lucernaria^ ^L. auricula^ Order =PEROMEDUSÆ= (/Umbrella conical and divided by transverse constrictions; four interradial tentaculocysts/) ^Pericolpa^ ^P. quadrigata^ Order =CUBOMEDUSÆ= (/Umbrella four-sided, cup-shaped; four perradial tentaculocysts/) ^Charybdæa^ ^C. marsupialis^ Order =DISCOMEDUSÆ= (/Flattened, saucer-like or disk-shaped umbrella; radial tubes branched; eight tentaculocysts/) Suborder ~CONNOSTOMÆ~ (/Very small; marginal tentacles; short and solid; mouth square without arms/) Suborder ~SEMOSTOMÆ~ (/Square mouth with four long arms; tentacles long and hollow/) ^Aurelia^ ^A. flavidula^ ^Cyanea^ ^C. arctica^ ^C. fulva^ ^C. versicolor^ ^Linerges^ ^L. mercurius^ ^Pelagia^ ^P. cyanella^ Suborder ~RHIZOSTOMÆ~ ("/Root-mouth/") (/Mouth obliterated by growth of oral arms across it; tentacles absent/) ^Cassiopeia^ ^C. frondosa^ [pg134] CLASS =SCYPHOZOA= THE LARGE JELLYFISHES