REPORT ON THE SIPHONOPHOR^E. 245 



different appearance according to the state of contraction of the different persons 

 composing it. In the strongly contracted state (fig. 6) it is nearly spherical, scarcely 

 larger than the dome-shaped nectosome above it ; in the highly expanded state it is 

 three or four times as large, and presents a most elegant aspect. The numerous 

 cormidia (forty to fifty in the figured specimen) are arranged around the central 

 spirally-turned trunk in a large dexiotropic spiral (or Delta-spiral), whilst the spiral 

 arrangement of the nectophores is an opposite one (lseotropic or Lambda-spiral), similar 

 to that of the cnidoband in the tentilla (PL X. fig. 23). The spiral axial trunk (fig. 7) 

 is articulate, and its pink central canal (etc) runs near the concave dorsal side. 



Cormidia (figs. 1, 6, 7). — The cormidia, which compose the siphosome, are arranged 

 in this species in an irregular manner, and disposed in a different way from 

 those of other nearly allied species. It may represent, therefore, a separate genus, 

 Forshdioma. The trunk of the siphosome (PI. IX. fig. 7, a), which is distinctly 

 articulate, bears the series of cormidia on its convex ventral side, where they arise 

 from equidistant nodes, or annular constrictions of the stem. Usually each loose 

 cormidium is composed of four different medusomes, viz., (l) a long-stalked siphon, 

 with its tentacle and numerous bracts ; (2) a stalked cyston, with a palpacle and a group 

 of bracts ; (3) a stalked palpon, with a palpacle and a bunch of bracts ; (4) a gonostyle 

 with a sexual palpon and a monoclinic gonodendron. This kind of regular composi- 

 tion is probably the original one, and is characteristic of this species. It is, however, 

 not quite constant, but subject to some individual variations, which may be partly 

 accidental. A further accurate examination and comparison of the composition of 

 the loose cormidia is particularly required in this as well as in all other Forskalidse 

 hitherto described. 



Bracts (figs. 1, 7,6, 10-18). — The innumerable hydrophyllia which cover the ir 

 siphosome are attached as well immediately to the trunk of it as to the pedicles of the 

 siphons, and to the bases of the pediculate cystous and palpons. Their number amounts 

 to more than a thousand in the largest specimens. The greatest number of these 

 bracts are small or of medium size, and of simple form (figs. 10-13); some of them 

 become larger and are developed in the form of large protective scales (figs. 7, b, 17, 

 18) covering the convex outside of the siphosome (fig. 1). These larger bracts are 

 three-sided prismatic, more or less asymmetrical, with a concave smooth lower or distal 

 face, and a convex dentate upper or proximal face. This latter bears usually a strong 

 dentate longitudinal crest, and the two lateral edges are also armed with a few teeth. 

 The smaller bracts have no crest and dentation ; they seem to fill up the intervals 

 between the larger, and are of very irregular form and different sizes (compare figs. 

 10-14). A blind longitudinal bracteal canal arises from the trunk and runs near the 

 concave inferior face of the bract. 



Siphons (figs. 1, 6, s, 7, s, 8, 9). — The polypitesare large, 10 mm. to 15 mm. long, and 



