[13] ALBATROSS EXPLORATIONS. 515 



is Aetinostola callosa V. (fig. 24), which often becomes 5 or 6 inches across 

 the body, and is usually somewhat higher than broad. It has a large 

 number of short, thick tentacles, usually deep orange in color, while the 

 body is lighter, varying to salmon or pale ilesh-color, and has a smooth 

 leathery texture and warty surface. This and the two preceding, 

 when living on the deep-water muddy bottoms, have the habit of firmly 

 inclosing a large ball of mud, often 2 or 3 inches in diameter, in 

 the base. This is done by the basal disk first spreading out and then 

 descending into the mud, when its edges contract so as to produce a 

 hollow bulb, often with only a small central opening below. This bulb 

 serves as an anchorage in the mud, but it is probable that all these 

 species, at first, when very young, adhere to bits of corals, worm-tubes, 

 shells, or some other solid substance, by a flat base, as usual with 

 Actinians in shallow water, and that the base gradually becomes bulbous 

 when it grows beyond its small support, for we often find young speci- 

 mens thus attached, and have observed the bulb in all stages of forma- 

 tion. In some cases one half the base would be flat, and adherent to a 

 shell, while the other half would have the bulbous form, inclosing mud. 

 Moreover, when these same species inhabit hard bottoms, covered with 

 shells and stones, as often happens, large specimens occur broadly 

 attached by their flat bases, so that this must be regarded as a special 

 adaptation suited to the peculiar conditions of muddy bottoms, but not 

 yet become a permanent character of the genera, nor even of the spe- 

 cies, so far as we have been able to discover. 



Within the hollow bulbs, mixed with the mud, or next to the base 

 itself, we usually find a number of chitinous pelicles, which have been 

 secreted by the basal disk and cast off from time to time. This is not 

 confined to either of the several genera that have bulbous bases, but is 

 common to all. It indicates that the same ball of mud, or portions of it, 

 at least, must be retained for a long period, or perhaps through life, 

 for it is probable that individuals thus anchored in the mud do not 

 move about at all, but ever afterwards remain fixed. Indeed, I have 

 good evidence that some large individuals of A. nodosa attached to 

 stones and shells remain fixed in the same place for years, without any 

 disposition to creep about, and perhaps they may lose this power, more 

 or less, as they grow old, though they certainly have it while young, as 

 do most shallow-water species. The formation of the basal bulb in 

 these Actinians, and in the Alcyonium above mentioned, throws much 

 light on the probable origin of the specialized muscular basal bulb of 

 the Pennatulacea. 



A remarkable new genus [Gondul mirabilis) has been recently de- 

 scribed by Koren and Danielssen,* which is attached by an adherent 

 base, as in Aleyonium, but has the polyps arranged on bilateral ob- 

 lique ridges, as in many Pennatulacea, and with four axial tubes, 



* Bergen's Museum, Nye Alcyonider, Gorgonider og Pennatulider til Norges Fauna, 

 p. 19, pi. 10, 1883. 



