352 Proceedings of the Royal 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 towards 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 half 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-stalk with two ovaries, the scleroderm covered by layer of 

 colletoderm. 



8. Ovary with colletoderm and scleroderm removed, showing layer of 

 ova between endoderm and ectoderm. 



9, Advanced stage of same: a, ruptured scleroderm; b, ectoderm; c, en- 

 doderm ; d, layer of colletoderm. 



10. Same, with ova extended into gelatinous nest. 



III. 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 



