MICROSCOPICAL STUDIES IN MARINE ZOOLOGY. 



BY JAMES HORNELL. 



Study I. — Haliclystus (Lucernaria) octoradiatus. 



THE pleasures of shore-collecting are many, and the one I fancy 

 the most enjoyable, is trudging about among gay weed-decked 

 pools and dyke-formed gutters in search of those delicate fern-like 

 sea-sprays, the Zoophytes. Here on this coarse brown Fucus are 

 numbers of serrate spikes of a Sertularian, bringing to memory 

 Silurian graptolites, while in that pool tiny pinnate fronds anchored 

 to the very rock itself, bespeak a Plumularian. Coryne too on this 

 Jersey coast is not infrequent, twining its long clubbed branches 

 among the finer weeds. But the vast sea-meadows or prairies as the 

 French call them, are equally prolific and harbour many beautiful 

 species never met with in rock pools. These meadows — where grows 

 the strange Zostera, a true flowering plant that has entirely renounced 

 fealty to its old home on dry land — are at times of spring tides fre- 

 quently left uncovered for short periods, and then .we must watch our 

 chance. Campanularia and Clytia we may meet with, but by far 

 most conspicuous are rather large brownish bells of exquisite outlines 

 — that here and there are anchored to the long green blades of the 

 Zostera. 



Such are easily recognized as Haliclystus octoradiatus, in these 

 parts the chief representative of the Lucernarians. In size these 

 bells (Fig. 1) are about one inch in height by nearly the same across 

 the oral face. The margin of this is drawn out into eight points, 

 each furnished with a bunch of closely set and numerous capitate 

 tentacles. In the centre is the mouth, standing up quadrangular 

 and prominent. The four angles (of the mouth) mark the four 

 primary radii that can be made out in these animals, and are usually 

 known as the perradial lines or radii. In allied forms, e.g. the 

 scyphistoma stage of Aurelia, these first radii are marked by the 

 appearance of the first four marginal tentacles. The second four 

 tentacles are alternate with the first and mark the secondary radii or 

 interradials. In Haliclystus their positions are the radial lines 

 beginning at points midway between the mouth angles. Thus they 



