I20 TF.STACELT-A SCUTULUM, SOWKUr.Y. 



When examining gravel pits and sections I have very frequently 

 taken away with me a sample of the smaller stuff for examination at 

 home, and I found the proportion of Lower Greensand chert in these 

 samples was as follows : — 



Glacial Gravel, Hendon, 6"5 "/„ ; the large pit at Gray's 

 Brickfield, from a bed which, I believe, to be under 

 the Corbicula fluminaiisho.^, 5*5 %; Westleton Shingle, 

 Coopersale Common, 37 % ^ Thames Gravel, Up- 

 minster Railway, south of Back Lane Bridge, 2*9 °'„; 

 Hornchurch Railway gravel above the Boulder Clay, 

 2'o"/o; Glacial Gravel, Rolstons, near Writtle, o"8 "/o ; 

 Thames Gravel, Walthamstow Railway, o'6 % ; Glacial 

 Gravel, Greensted Church, 0*5 "/(,. 



These figures seem to show that in pre-glacial or early glacial 

 times there was a considerable flow of water from the south towards 

 the north, unless indeed it can be shown that this chert cauie from 

 the Lower Greensand of the north. 



I am not, however, at present able to find any record of such a 

 rock occurring in the Lower Greensand north of London, but the 

 matter requires further investigation. 



TESTACELLA SCUTULUM, SOWERBY. 



HP HE specimens of this worm-eating slug, recently exhibited at a 

 meeting of the Essex Field Club,' have furnished the material 

 for some experiments and called forth a paper in the " Zoologist " from 

 our member, Mr. W. M. Webb, F.L.S.,- dealing with the way in 

 which this highly specialised mollusc catches and swallows its prey. 



The first part of the paper is taken up by a review of the pre- 

 vious accounts of the matter, which, however, tend to the formation 

 of somewhat exaggerated and indefinite ideas on the subject. A 

 description is then given of the writer's experiments ; he found that 

 certain stimuli, such as the touching of the retracted anterior end of 

 the slug by a living earthworm, or with a camel's hair brush, or again 

 with a drop of water in the case of Testacella maiigei, Fer., gave rise 



1 Essex Naturalist, vol. vii. (1893), p. 46. 



2 On the Manner of Feeding in Testacella scutulum, by Wilfred Mark Webb, F.L.S, St.<iff 

 Demonstrator in Biology to the Essex County Council, "Zoologist," vol. xvii. (1893), pp. 251- 

 2S9, plate J. 



