193 EEPORT— 1866. 



sea-bottom, at cousiderable depths, differs in its composition. Professor Sars 

 noticed that large Erachiopoda, stony corals, and Poljzoa, as well as certain 

 Mollusca (e. g. Anomia and Saxicava), which are peculiar to a hard or even 

 to a rocky bottom, inhabit a depth of 300 fathoms ; and Dr. Wallich found 

 a living Scypula attached to a stone at the depth of 682 fathoms. Captain 

 Beechey's dredgings off the Mull of Gallowaj', in l-iS fathoms (as reported 

 by the late Mr. Thompson of Belfast in the Annals and Magazine of 

 Natural History for September 1842, p. 21), yielded live specimens of Chiton 

 fasc'icidaris, C. cinercus, Trochits miUegranus, and Tnplion Barvkenf^is, all of 

 which are inhabitants of hard or stony, and never of soft ground, besides dead 

 shells of the same and similar species. The Hebridean sea-bed, at very 

 moderate depths (which Dr. Wallich would call " shallow water "), mainly 

 consists of a soft and more or less tenacious mud, mixed with stones of dif- 

 ferent sizes, and resembling in its composition the boulder-clay or 'glacial 

 drift of Scotch geologists. It tells us of rocks ground down by glaciers year 

 after year in an arctic region — of the mud produced by such attrition being 

 carried into the sea in the thawing-season by overwhelming floods, " non sine 

 montium clamore " (see Dr. Kane's description of the great Humboldt gla- 

 cier) — of its dispersion over the sea-bed by the action of tides and currents — 

 of the deposit thus formed being inhabited by a variety of animals of a high 

 northern tj'pe during a long and quiet course of time — of the sea-bed being 

 elevated by slow degrees above the surface of the water by an agency which 

 we cannot satisfactorily explain, but which may have been volcanic or perhaps 

 caused by steam * — of the consequent extermination of these marine animals 

 — of an interval during which the raised sea-bed was dry land — of a gradual 

 amelioration of the climate — of another oscillation of the earth's crust in 

 a downward direction, when the surface of the land, covered by its former 

 deposit, again became the bottom of the sea — and of a fresh succession of life, 

 which is still in existence. Thus a cycle of similar events continually recurs. 

 Nothing is lost or altogether perishes ; all the old materials are iiscd iip, and 

 assume new forms. It is the fashion to quote Lucretius. I will only indulge 

 in two lines ; they seem not to be inapplicable to the present subject : — 



" Hue accedit uti quicque in sua corpora rursum 

 Dissoluat natura neque ad nilum interemat res." 



The kind assistance of Mr. Alder, Dr. Carpenter, the Rev. A. M. Norman, 

 Messrs. Henry and George Brady, Dr. M'Intosh, and Mr. Peach — all of them 

 experienced zoologists — enables me to supplement this report with notices of 

 other departments of the invertebrate fauna, which have resulted from the 

 last grant made to me. Several new species, especially among the smaller 

 Crustacea, have occurred ; and our knowledge of geographical distribution has 

 been not a little advanced by the work. Mr. Norman's services especially 

 deserve acknowledgment. 



I have made my usual contribution to the British Museum. 



Description of a new species of Montacuta. 



MoNTAcuTA TUMiDULAf, Jeffreys. 



Shell rhomboideo-oval, rather gibbous, thin, semitransparent, glossy, and 

 prismatic ; sculpture, numerous and close-set, delicate, microscopical con- 

 centric strias : colour yellowish : epidermis fine and silky : margins, on the 



* Vide Mr. R. A. Peacock's pamphlet ' On Steam as the Motive Power in Earthquakes 

 and Volcanoes, and on Cavities in the Earth's Crust.' Jersey, 18G6. 

 t Somewhat swollen. 



