XXXI.—On New Forms of Marine Diatomaceæ, found in the Firth of Clyde and in Loch Fine

Abstract

In two papers read before this Society, I have very fully described the Diatomaceæ of the Glenshira Sand, which is very remarkable both for the large number of species found in it, which is certainly more than 320, and for the circumstances in which it must have been deposited. There can be no doubt, from the nature of the locality, which I have lately visited, that this bed was formed in the bottom of the Dhu Loch, a shallow fresh-water lake, at that time extending about two miles farther up the valley than it now does, and being at a higher level. In consequence of a rise in the level of the land, or a fall in that of the sea (from which—that is, from Loch Fine, the lower end of the lake is separated by a narrow and low barrier, through which the waters of the lake pass to Loch Fine), the lake has long ago been drained, till its upper end is nearly two miles from the point it must have reached when the bed of sand was formed. The present level of the lake is considerably lower than it was then; the precise difference I had no means of ascertaining, but I believe it is about 30 feet.

Phylogenetic position of eight Amphora sensu lato (Bacillariophyceae) species and comparative analysis of morphological characteristics

“…However, the sketches in earlier literature did not accurately illustrate the girdle area types for species definition. Examples of this can be seen in the girdle area type pictures of A. granulata (Gregory 1857 , Fig. 96b) and A. proboscidea (Gregory 1857, Fig.…”

“…To acquire more accurate data on the size of Amphora, natural samples will need to be tested. However, many studies (Gregory 1857, Van Heurck 1896, Péragallo and Péragallo 1908, Cleve-Euler 1953, Levkov 2009) have shown that the same species from different locations can have various sizes. For example, the 70-150 μm cell lengths of A. proteus in England, Belgium, Germany, and Norway (Van Heurck 1896) were much larger than the 15-60 μm cell lengths in the Firth of Clyde and in Loch Fine (Gregory 1857).…”

“…However, many studies (Gregory 1857, Van Heurck 1896, Péragallo and Péragallo 1908, Cleve-Euler 1953, Levkov 2009) have shown that the same species from different locations can have various sizes. For example, the 70-150 μm cell lengths of A. proteus in England, Belgium, Germany, and Norway (Van Heurck 1896) were much larger than the 15-60 μm cell lengths in the Firth of Clyde and in Loch Fine (Gregory 1857). Therefore, size differences might be the result of cell division, sexual reproduction, life cycle and different environments (Veselá et al 2009, Davidovich et al 2012.…”

Colony formation and valve morphology in the marine benthic diatomDimeregramma fulvum

“…The apical pore fields at the valve ends correspond to the "unstriated knobs at each end of the valves" of Gregory (1857). The absence of rimoportulae, the valvar striation with virgae, and the chain formation all indicate that the species should form a part of the generic concept of the genus Dimeregramma.…”

Symmetry and sex in Bacillariaceae (Bacillariophyta), with descriptions of three newNitzschiaspecies

“…distans' in his ecological studies of Loch Goil. However, N. distans has a symmetrical outline and the raphe is close to the midline of the valve (Gregory, 1857), not eccentric as in the Loch Goil forms. An irregular texturing of the dorsal part of the valve in some of the Goil forms reminded us of H. segmentalis (Brun, 1895), but apart from this no similar diatoms were found illustrated in floras (e.g.…”