352 Proceedings of the Royril Physical Society. 
to the cavity of the stomach, of a brilliant reddish orange. 
I have also found very minute specimens of this species at 
Gran ton 
3. Laomedea decipiens. (New Species.) 
Polypary minute ; stem filiform flexuose, with from one 
to five branches, each bearing a cell ; the stem is annu- 
lated with about five rings above the origin of each 
branch ; the branches are annulated throughout ; cells 
widening rapidly tow^ards the top, with even double 
rims. Polyp, with about sixteen tentacles and trumpet- 
shaped proboscis. 
This pretty little Laomedea resembles much the Laomedea 
neglecta of Alder, except that the margin of the cell is even, 
and has the appearance of being double for about lialf its 
length from the rim, though, from the extreme delicacy of 
the cell, this character is only made out with difficulty. 
The reproduction of this zoophyte resembles exactly that of 
Laomedea lacerata^ except that each gelatinous nest of A . 
decipiens contains only three ova, while that of L. lacerata 
contains six or eight. 
Description of Plate XV. — Atractylis arenosa. 
Fig. 7. Polyp-stolk with two ovaries, the scleroderra covered by layer of 
colletoderm. 
8. Ovary with colletoderm and scleroderm removed, shovving layer of 
ova between endoderm and ectoderm. 
9, Advanced stage of same: a, ruptured scleroderma b, ectoderm; c, en- 
doderm ; d, layer of colletoderm. 
10. Same, with ova extended into gelatinous nest. 
Ill, On the Geological Age of the Pagan Monuments of the Outer 
Hebrides. By Captain F. W. L. Thomas, R.N. 
Some recent observations made upon the geological changes 
that have taken place since the so-called Druidical circles 
were erected in the Long Island, will, it is presumed, be inter- 
esting to the Society ; although any conclusions from these 
observations can only be valued as first approximations to a 
knowledge of the era of the unknown founders of these gigan- 
tic monolithic structures. 
It forms no part of the present subject to describe these 
monuments farther than to state, that, as in the Orkneys, in 
one locality of the Lewis several of these circles are placed 
