Stkphenpon — Certain Actiniaria collected off Ireland. 



■ )■> 



almost a whole gastropod shell in its base, including the point. So that 

 although these specimens superficially resemble //. digitata, the presence of 



basal swellings to the tentacles, and the arrangement of the ridges, show 

 them to be really A. richardi. In anatomy a typical case shows nothing 

 essentially different from the previously described form of richardi. The 

 muscle-pennon of the mesentery is certainly rather like that "I' digitata, 

 but the sphincter is not; and there is no essential difference even in the 

 former. 



IV. There are other specimens in the collection which form links between 

 the two extremes above described. All sorts of curious bases are represented, 

 which are neither cups nor discs, but intermediate — cups with thick or 

 irregular walls; discs with the ed^es rolled in: bases in which half is 

 adhesive, half more or less incurled, &c. Some are very battered and irre- 

 gular. The ridges of the capitulum may be very marked or very faint ; the 

 basal swellings of the tentacles are present in every case examined, but may 

 he so much reduced that they may be described as ''almost absent," and 

 great care is needed to detect them. On the other hand, they may be larger 

 than the tentacles themselves, and all grades are found. The base, when 

 adhesive, often does not expand much, but in a few cases it is very broad 

 indeed. (For figures showing external appearance of five specimens, see 

 PI. XIV, figs. 3 and 9 ; and PI. XV, figs. 5, 6, 11.) 



V. The specimen which I have most hesitation in referring to the species 

 richardi (though it is undoubtedly an Actinauge) is the one illustrated in 

 PI. XV, figs. 6 and 10. There is no other specimen among the 20o with quite 

 such a distinct development of tubercles and accuracy of arrangement of 

 ridges. Here the ridges are formed not only by fusion of basal swellings of 

 fourth-cycle tentacles — the third-cycle ' tentacles join in, and the ridge is 

 consequently triple. But this is present in some typical specimens, too. This 

 isolated example has all the typical richardi features and arrangement of 

 swellings, and it is only the fact that the details of its sphincter and mesen- 

 terial musculature do not agree with the others that makes me hesitate. 1 am 

 inclined to think that further investigation may show that here, too, other 

 specimens will be intermediate, but we shall see. 



VI. Specific characters of Actinauge richardi as a whole: — 

 Base a mud-clasping cup or an adhesive disc, or intermediate; scapus 

 more or less tuberculate; cuticle well or poorly developed : coronal tubercles 

 twelve (or approximately); capitular ridges twelve, very variable, and formed 

 by the continuation down the capitulum of the basal swellings of the tentacles 

 of the fourth cycle, sometimes joined by those of the third : they may be 

 practically obsolete; tentacles in five cycles, the outermost cycle without 



R.I. A. PKOC. VOL. XXXIV. SECT. B. \ 



