24* 



internal testaceous shield ; but the common black 

 or brown slug has none, or the mere unformed 

 rudiments. 



Like the shells which are found enveloped in some 

 of the marine Mollusca, we consider, with the 

 French naturalist Brard, that they are entitled to 

 classical arrangement, and merit a place among 

 the testaceous productions of our islands. 



14. LIMACELLUS Parma. Shell thin, flat, oblong, a 

 little concave, with a membranaceous margin. 



Limacella Parma. Brard, p. 110. t. 4>.f. 1, 2, 9, 10. 



Z)e Ferussac, tab. 4. Jig. 4. 



Lister, tab. anat. 5. Jig. 5. 



Shell about six lines long and four broad, thin, semi- 

 transparent, yellowish-white, concave on the inside, 

 which is sometimes sprinkled with minute crystal- 

 like shining particles, a little convex and trans- 

 versely wrinkled on the outside ; with the edges 

 membranaceous : on the top, or broader extremity, 

 is a small central prominence, or apophysis of ad- 

 hesion, by which it is attached to the animal ; the 

 lower extremity very thin and rounded. 



