214 



- KNOWLEDGE ♦ 



[O.T. 19, 1883. 



SEA ANEMONES 



AT THE FISHERIES EXHIBITION. 

 By Thomas Kimber. 



VI.— THE CAVE-DWELLER. 



Actinia troglodytes (Johnston). Scolanthus sphcero'ides (Holds- 

 worth.) 



BY the early writers this anemone was called riduata 

 (widowed). Dr. Johnston adopted, after Mr. Price, 

 the more distinctive term tro;/!odi/ies, cave-dweller (from 

 rpwy\oci)Tiir, one who creeps into holes). Though abundant 

 in many localities, and widely distributed all round our 

 shores, it is not easily found by unpractised collectors, on 

 account of its retiring habits. Its favourite custom is 

 to hide itself in holes and crevices of rocks, in shallow- 

 tidal pools, and on the floors of caves. When scores of 

 them are expanding their flowers in profusion at the 

 bottom of the bright water, they may easily be overlooked, 

 since their mottled disks and barred tentacles resemble the 

 sand and gravel in the pools where they live. They 

 shrink on the slightest alarm, and hide themselves in the 

 sand or mud, protruding only their tentacles perpendicu- 

 larly, and sometimes barely the tips of these organs can 

 be seen. When sand or mud is not available, their con- 

 cealment is frequently secured by suckers on the column, 

 to which fragments of shells and quantities of gravel be- 

 come firmly attached, and even when placed in a tank 

 they frequently retain these foreign bodies with great 

 obstinacy for a considerable period. 



mf4\i^ 



Fig. 1. — Disk, with B mark on Tentacles. 



Fig. 1. The Disk, dx. — The chief characteristic feature 

 of troglodytes is the black mark at the foot of each tentacle, 

 which is nearly always relieved by two white curved spots, 

 forming together a strong resemblance to the Roman 

 capital B. The tentacles are numerous, in fine specimens 

 between two and three hundred ; they are set in four or 

 five rows, and, as usual, the largest are innermost. 



There is no species of British anemones that varies so 

 •widely in colour of disk and tentacles. The general 

 pattern of the disk is well described as resembling the 

 pencilled pattern of a snipe's feather. The bright orange, 

 grey, and blue black varieties are the handsomest, and 

 there are fifteen or sixteen others derived from the admix- 

 ture of these colours. 



The marking of the disk itself, apart from the tentacle, 

 is pretty constant. Each radius is light grey from the B 

 marking on the tentacle to half way to the mouth ; then 

 there is a bright white spot, as shown in the figure, fol- 

 lowed by a thin line of yellow, or drab edged with black, 



which is continued to the lip. The mouth is usually 

 whitish. 



Generally there is no difficulty in determining this 

 species. The B mark is the most certain distinction, and in 

 the few instances where this is not discernible, the firm 

 texture of the column and base, Mr. Holdsworth points 

 out, is "a fair mark." Troglodytes is not so easily injured 

 as most species are, and his adhesive power is compara- 

 tively weak. 



Fig. 2. 



Fig. 2. The Column. — The general colour is green, with 

 an admixture of brown, producing various shades of olive, 

 and sometimes dark brown columns are met with. The 

 lower half is marked with pale stripes, which are broader 

 towards the base. Above these stripes the column is 

 smooth, and the suckers are there marked by pale spots. 



In large specimens the column is from 2 inches to 

 4 inches in height, and from 1 inch to 1 .'. inches in dia- 

 meter, while the disk has fully 2 inches in breadth of 

 bloom. Morecambe Bay and Torquay give specimens with 

 orange and rose-red tentacles and disks ; while from 

 Boulogne they are obtained with rich full lake and light 

 lilac colours displayed in their flower. 



Mr. Holdsworth met with examples of this species in 

 deep sands or mud at Seaford, near Beachy Head, so 

 peculiar is their habits, that for weeks in succession they 

 kept retracted both disk and base so as thereby to assume 

 the form of a flat bead or an onion, and evinced no dis- 

 position to attach themselves by their bases after the- 

 manner of their kind. 



From this circumstance he named them sphero'ides, 

 believing them to be a distinct species, living entirely free 

 from attachment ; but he has since seen reason to modify 

 his views. 



On soiae occasions, in the glass tank or vase, examples of 

 this peculiar type will attach themselves by the suckers on 

 the upper part of the column, and then they appear in an 

 almost inverted position, with their base uppermost, where 

 their disk ought to be. Specimens of this class are called 

 by difl'erent writers vagabond, homeless, restless, and, 

 besides receiving other hard names, they are described in. 

 this stage of their existence as " sowing their wild oats," 

 after which period they settle down, lead a quiet life, and 

 become respectable. They are then a credit and an orna- 

 ment to any aquarium, and perhaps all the more cherished 

 for being reformed characters. This roving free habit 

 marks especially the mud-dwelling class of troglodytes. 



The disposition to be at all times less firmly attached by 

 the base than other species, and the habit for lengthened 

 periods of living quite detached, particularly distinguishes 

 Troglodi/les as constituting an intermediate link between, 

 the permanently free and the permanently attached forms. 



