2 1 2 Miscellaneous. 



a region without the slopes necessary to produce moving glaciers. 

 The Mammoth may be supposed to have passed between Asia and 

 America at this time. At a later date, when Bering Straits were 

 opened and the perennial accumulation of snow ceased on the low- 

 lands, the clay was probably carried down from the highlands 

 and deposited during the overflow of rivers. Over this land the 

 Mammoth roamed, and wherever local areas of decay of ice arose 

 bogs would 1)6 produced which served as veritable sink-traps. The 

 Author considers it probable that the accumulation of ' ground-ice ' 

 was coincident with the second (and latest) epoch of maximum 

 glaciatiou, which was followed by an important subsidence in 

 British Columbia. 



December 6, 1893.— W. H. Hudlcston, Esq., M.A., F.R.S., 

 President, in the Chair. 



The following communication was read : — 



' On a Variety of Ammomfes {Stejylv.nioceras) suharmafxa, Young, 

 from the Upper Lias of Whitby.' By Horace \V. Monckton, Esq., 

 F.L.S., F.G.S. 



Tiie Author describes an ammonite found by himself in 1S74 

 near Sandsend, 3 miles north-west of Whitby. He thinks it was 

 not actually in situ, but lying with a number of nodules on the 

 floor of an old alum-pit, although he has no doubt that it is from 

 the Alum Shale of the Upi)er Lias. A peculiar arrangement of the 

 costae as they cross the siphonal area distinguishes the specimen 

 from other AVhitby ammonites known to the Author. It bears a 

 strong resemblance to a shell figured as A. subannafKs by D'Orbiguy, 

 ' Terr. Jurass.,' pi. Ixxvii., but is unlike the figures of that species 

 given by other authors. 



MISCELLANEOUS. 



On the Jans of Hirudinea, By Jac. M. Croockewit. 



Haycraft's discovery of a substance in the head of Jlintdo mdU- 

 ciiiu/is, wliich is able to jireveut the coagulation of the blood, has 

 hud the ettbct of directing attention afresh to the jaws and to the 

 BO-callcd salivary glands of leeches. 



I now venture to make a ])rovisional communication of certain 

 details of the I'esults which 1 have obtained with reference to these 

 organs in studying Hirmlo meilicinaJis and Aiihisto)nu)ii ijulo. 



it is well known tliat in tlie head of tliruifo there is found a very 

 large nunil)er of unicellular glands, tlie excretory ducts of which, 

 in the shape of long, narrow, uiululating tubes, partly run between 

 the epithelial cells of tin* pharynx, and jiartly open on the free edges 

 of the jaws. In Aiihistomnni the number of the glands is much 

 pmaller, and in this animal they open, if not exclusively, at any rate 

 almost all upon the edges of the jaws. The secretion contains a 



