[Illustration: /Pennaria tiarella/; a branch, natural size.] ^P. gibbosa.^ A species similar to /P. tiarella/, found on the coast of Florida. [Illustration: PLATE XLII. Corymorpha pendula. Clytia bicophora.] [Illustration: PLATE XLII, A. Obelia longissima. Clytia poterium. Sertularia pumila.] GENUS ^Bougainvillea^ ^B. superciliaris.^ This hydroid is found in tide-pools on the New England coast, growing in clusters, about two inches high, attached to rocks or to mussel-shells. The stem is very slender, and branches. It is red in color. The medusæ which it liberates are found in great numbers in the spring. The tiny swimming-bells are nearly globular. The tentacles are long, are arranged in four clusters on the margin, and extend in every direction. The manubrium is yellow and short, and the mouth is concealed by four clusters of short tentacles. On these oral tentacles [pg125] the eggs of the animal are produced. In its habits it is sluggish, often remaining in one position for several days. THE CAMPANULARIANS The hydroids which have an open, bell-shaped cup at the termination of a short, stalk-like stem, or branchlet, are mostly campanularians. This division embraces jellyfishes of different families. Many medusæ cannot be referred with certainty to the hydroids from which they sprang, and the medusa-buds of many of the hydroids have not been noted. GENUS ^Obelia^ (Plate XLII, A) ^O. commissuralis.^ This is a delicate, much-branched hydroid, five to six inches long, found at low-water mark in tide-pools, attached to stones and seaweeds, along the rocky shores from Nova Scotia to South Carolina. Its branches are arranged spirally and spread nearly at right angles to the main stem, and the main branches subdivide in a similar manner. Every interval of the stem has a slight curve, and at the base of every branch there are four or five rings. The ultimate branches, or pedicels, bear at their ends bell-shaped cups which have even edges, but are twelve-sided and slightly incurved. The pedicels are ringed for the whole length. The reproductive cups on short ringed pedicels are larger than the others, and occupy the angles of the branches. These cups are constricted and again expanded at the apex, forming an urn-like top. GENUS ^Eucope^