286 THE ZOOLOGIST. 



Several fine specimens were found by Mr. H. C. Snell in an 

 old asparagus bed at Buekburst Hill, and exhibited at a meeting 

 of the Essex Field Club* by the Secretary, Mr. William Cole, 

 who very kindly forwarded them to the present writer. One of 

 these slugs was laid on the damp surface of an old inverted 

 flower-pot saucer, and after a short time the animal extended 

 itself more or less completely (Plate I., figs. 1 and 2). An 

 earthworm was so placed that in the course of its progress it 

 came into contact with the anterior end of the slug. The result 

 of the stimulus was to make the Testacella draw in its tentacles 

 and head, and assume somewhat the position shown in fig. 8, 

 where a broad and more or less vertical front is exposed. Other 

 stimuli, as might well be imagined, such as the application of a 

 finger or paint-brush, may have the same effect. If when such a 

 stage has been reached the stimulus be gently continued, as it- 

 would be by allowing the worm to crawl up the slug's front, in 

 the centre of which a slight depression above the orifice of the 

 mouth seems to allow of an easier ascent, the tongue-like car- 

 tilage which carries the radula may be suddenly, and in the first 

 instance unexpectedly, shot out, the mouth opening to allow of 

 its protrusion (fig. 3). 



While the writer was cleaning a specimen of T. maugei, which* 

 was kindly sent to him, among others, by Mr. F. W. Moore, of 

 the Royal Botanic Gardens, Glasnevin, a drop of cold water fell 

 from the tap on to the front of the slug, which immediately pro- 

 truded its radula. The apparatus, which is milky white, appears 

 somewhat spoon-shaped looking at it from above (fig. 3 a), but 

 broader at the free extremity where there is a slight depression, 

 and as it comes to its limit of extension, the edges, as it were, of 

 the spoon bend upwards and inwards, making the hollow deeper 

 and at the same time narrower. 



The radula, or lingual ribbon, which follows the general form 

 of the strong basal cartilage, curling over its edges in front 

 and at the sides, is studded with a great number of chitinous 

 "teeth" arranged in rows; these are placed in such a position 

 that in the hollow of the cartilage the barbed shafts (figs. 6 a, ()b), 

 of which the}' mainly consist, all point towards the mouth of the 

 animal, while where the rows follow the ribbon over the outer sides 

 of the cartilage, they are larger (fig. 6) and directed upwards. 



* 'Essex Naturalist,' vol. vii. (1893), p. 46. 



