On Holtenia, a Genus of Vitreous Sponges

W. Thomson
1869 Philosophical Transactions of the Royal Society of London  
] XXVII. On Holtenia, a Genus o f Vitreous Sponges. W y v il l e T h o m so n , L L . BF .R.S. , Professor of Natural Science in Queen's , . D u r in g the deep-sea dredging cruise of Her Majesty's Ship «Lightning * in the autumn of the year 1868, the 6th of September was occupied in dredging at the depth of 630 fathoms in latitude 69° 36* N., and longitude 7° 2(V W., only about 20 miles beyond the 100-fathom line of the Coast Survey of Scotland, slightly to the westward of north of the Butt of
more » ... orth of the Butt of the Lews. The minimum temperature indicated by the mean of three ther mometers (which registered 47°, 47°*5, and 47°-6 F a h r . respectively) was 47°*3 F a h r , the surface-temperature being 52°'6 F a h r . During the day there were four successful hauls of the dredge, which came up each time full of a pale-grey tenacious mud, consisting in a great measure of minute amor phous particles of carbonate of lime mixed with coccoliths " and coccospheres." There was only a small proportion of the Globigerince and other minute Rhizopods which are so abundant and characteristic over the whole of the warm or " Gulf-stream " area of the North Atlantic. The mud was glairy, as if it had been mixed with white of egg; ahd it contained disseminated through it an immense quantity of extremely delicate siliceous organisms, spicules of sponges, and the shells of Radiolarians and Diatoms. Large Rhizopods of the genera A s t r o r h i z a, others were abundant \ and there was a somewhat scanty sprinkling of small forms belong ing to the higher groups, Echinoderms, Annulosa, and Mollusca. Besides a number of dead shells, chiefly of the Boreal or Scandinavian type, and several undescribed Echino derms and Crustaceans, the following species were procured living.
doi:10.1098/rstl.1869.0030 fatcat:ohcwl5jt5zgivclxaesstrhaza