Stkphknson — Certain Actiniaria collected off Ireland, 137 



Note on label: — "Disc and tentacles, colour vermilion ; column white." 

 Measurements. — Diameter of pedal disc, 4 cm. ; of column at narrowest, 

 32 cm. ; of oral disc and tentacles, 67 cm.; height of column, 48 cm. 



External characters. — fPl. XVI, fig. 41.) The pedal disc forms a wide 

 cup, with an even, oval rim slightly indrawn over it. It is filled with a 

 mixture of dirt and cuticle. Limbus well defined. The column slopes 

 gradually inwards from the base up, being narrowest just below the disc; but 

 at the top it suddenly widens out, so that its circumference at the margin 

 is much greater than at the base. The lower part has a moderately thick, 

 tough, flaccid, quite smooth wall, without visible cinclides. The wall of the 

 expanded upper part is thicker, and is thrown into irregular transverse folds, 

 covered with solid nodules or tubercles of various sizes. These are numerous, 

 but with no very definite arrangement, and not equally developed on all sides of 

 the animal ; on the whole, they increase in size from below upwards. Margin 

 tentaculate, irregular. Tentacles rather short, rather thin-walled and 

 flaccid, moderately slender, tapering, bluntly pointed. They are not fluted, 

 but have delicate transverse and longitudinal striations. All of them have 

 a swelling of solid mesogloea on the outer side at the base, not quite equally 

 developed all round the disc. They are arranged in two alternating marginal 

 cycles only, 72 - 72 = 144. Oral disc greatly expanded, thin-walled, and 

 flaccid, with radial ridges which correspond to the tentacles, but do not 

 quite reach the mouth. Lips prominent, showing the ridges and the two 

 grooves of the actinopharynx. 



Structure. — (i) Mi nti < Us. There are six pairs of perfect mesenteries, and 

 two additional unpaired perfect mesenteries, belonging to the second cycle. 

 These two are symmetrically disposed about the long axis of the body, and 

 their retractor muscles face one of the pairs of directives, on either side of 

 which they occur. There are five cycles — 6p. + 6p. + 12p. + 24p. + 31p. Last 

 cycle incompletely developed and very small. Xo gonads were visible on 

 dissection, but sections of a sector show young ova in mesenteries of the 

 third cycle. Aeontia ate present, but they are rather small In structure 

 they show differences from the mesenterial filament of almost exactly the 

 same nature as those described under V. pulchra. The perfect mesenteries, 

 as seeu in sections of a portion of the body at the level of the actinopharynx, 

 contain on the whole a good deal of mesogloea. "Where each mesentery leaves 

 the body- wall, its mesogloea is thick, and sends out on each side of it a few 

 fairly large and moderately branched stout processes PI. XVIII. fig. S , which 

 give the genuine '• reversed" appearance— as if, that is, the processes were 

 projecting the wrong way, from endoderm into mesogloea : of course this is 

 only apparent. These processes are more numerous and better developed 



R.l.A. PROC, VOL. XXXIV, SECT. B. ' T\ 



