108 PNEUMONOBRANCHIATA. 



I first indicated this species as being a native, in 

 1821, and Dr. Johnston, in 1828, and Mr. Alder, 

 more lately, have informed me that the variety is not 

 uncommon in the north of England. It is equally 

 common in my garden at Blackheath, found in com- 

 pany with Limax agrestis. 



Dr. Johnston more recently, in his list of Berwick- 

 shire Mollusca, stated that he believes his A. circum- 

 scriptus is merely a variety or immature state of A. 

 ater. He thought that it was probably the Limax 

 agrestis of Dr. Latham (Linn. Trans, iv. 85. t. 8. f. 

 1 — 4.), or the Limax marginatus of Muller. It 

 may be the young state of A. ater, for I do not recol- 

 lect ever to have seen any small specimens which 

 agreed with that species. 



