Royal Physical Society. 267 



polyps, are extruded from the summit of the ovisac, and fixing 

 themselves by their base, commence the development of a poly- 

 pary, like the parent zoophyte. . 



In male specimens, for this zoophtye is dioecious, the sper- 

 matic capsules resemble in shape and structure the ovarian 

 sacs of the female, except that instead of ova, we have a gela- 

 tinous plasma, secreted between the endoderm and muscular 

 layer, in which spermatic cells, and afterwards spermatozoa, 

 are developed. The spermatozoa of Tubularia were discovered 

 by Krohn in 1835. Their existence, of which there is no 

 room for doubt, has since been denied by Van Beneden and 

 Johnston. 



IV. Notice of two Fossils found in a bed of Shale beloiv St Anthony's 

 Chapel, Arthur's Seat. By James M'Bain, M.D., R.N. 



The short communication which I have to make to the Royal Physical 

 Society has reference to two fossil organisms found in a "bed of shale be- 

 neath St Anthony's Chapel. This bed rests upon amygdaloidal trap- 

 tuff, and is covered by another bed of columnar basalt, on which the cha- 

 pel is built. The bed can be traced from a few feet above the old arched 

 well, where it appears as a tough siliceous sandstone, passing upwards 

 for twenty or thirty yards, then following the general bending and cur- 

 vature of the great beds of amygdaloid and basalt, between which it is 

 intercalated, until it finally disappears under the detritus and soil, at the 

 northern and lower part of the cliff on which the chapel rests. It can be 

 e asily traced for fully a hundred yards, and is well exposed in seven or 

 eight places. It has been long known to the geological explorers of 

 Arthur's Seat that this shaly bed contained fossil organisms, apparently 

 of a vegetable character, to which the general term " fucoid" has been 

 applied. These vegetable-looking impressions are found in great abun- 

 dance in thin layers of shale, of which the bed is formed ; but hitherto, 

 so far as I am aware, without any special characteristic marks by which, 

 they could be assigned to any particular geological epoch. To facilitate 

 the investigation of the contents of this bed, one of the before -mentioned 

 exposed places was opened to some extent in June 1854. On visiting the 

 spot a few days afterwards, and chipping a portion of the thin lami- 

 nated clay, I found a small tooth imbedded in it. The length of the 

 tooth was about seven-tenths of an inch ; its form curved, pointed, and 

 marked by longitudinal striae, diverging from the central axis at its 

 base. On showing the tooth to Professor Fleming, and comparing it 

 with specimens in his collection of fossil fishes, he had little doubt but that 

 it belonged to the genus Holoptychius — most probably to the Hoi. Hib- 

 bertii — a fossil fish found abundantly in the Carboniferous system, and 



VOL. I. 2 A 



