STEPHENSON — Certain Actiniaria collected off Ireland. 151 



The tubercles of the scapus vary both in extent and development. Some 

 times they die out before the base is reached, leaving the lower pari of the 

 column smooth. In other cases small, low tubercles almost reach the base; 

 every stage and gradation may be found. The tubercles themselves vary 

 "•really in size and form in different specimens ; they may be large, prominent, 

 and spiky, or prominent and rounded, or indefinite, or almost obsolete. They 

 often have cuticle developed on them or between them, and there is usually 

 dirt in the cracks between them, The cuticle varies considerably — there 

 may be much or little of it, or practically none. Sometimes the tubercles 

 are densely crowded, sometimes scattered, sometimes intermediate; they 

 may be very low and inconspicuous. It is -always possible, however, to 

 distinguish more or less clearly, either exactly or approximately, twelve 

 tubercles which mark the uppermost limit of the scapus — sometimes twelve 

 short rows of them even. These tubercles are not distinctly marked off' from 

 the rest, but the others show, as a rule, no definite arrangement ; at best they 

 tend to be arranged in vertical and horizontal rows. Even these " coronal " 

 tubercles, although sometimes quite clear, may be very irregularly and 

 indefinitely developed, often merging into the ridges of the capitulum, so 

 that when the latter also are indistinct, the difference betwen scapus and 

 capitulum is barely recognizable. Sometimes the body is distended, and then 

 it has an extremely thin and flabby (but tough) wall, with the mesenterial 

 insertions showing through it, and the tubercles separated by smooth inter- 

 spaces. But various grades of thickness are found, and sometimes it is very 

 thick. Many of the specimens are more or less contracted (the capitulum 

 being quite introverted when contraction is complete), but a few are well 

 expanded, with disc displayed, actinopharynx puffed out. and capitulum 

 turned back. (PI. XV, fig. 5.) Acontia are well developed, and frequently 

 a tuft of them protrudes from the mouth. The general plan of tentacle- 

 arrangement above described is universal — that is to say, the inner tentacles 

 have basal swellings: the fourth-cycle tentacles have swellings which run 

 out over the edge of the capitulum; and the small outermosl tentacles have 

 none. But the actual details of the capitulum are peculiarly variable, even 

 on opposite sides of the same specimen, sometimes. On the whole, one can 

 trace a more or less definite connexion between the basal swellings of the 

 fourth-cycle tentacles and the "coronal" tubercles — this varying in distinct- 

 ness in different cases. (PI. XVI. figs. 29, 32, 33; PI. XIV. fig. 3.) Some- 

 times, however, the ridges are very irregular or indefinite; and the con- 

 tinuity between the tubercles and the fourth-cycle swellings may be nearly 

 absent; the ridges, also, may be irregularly broken up by transverse inter- 

 ruptions into tubercles. In some cases, even, the capitulum may be termed 



