ARIOtt. 23t 



According to Mabille the Swedish A.fasciatus, Nilsson, is a 

 closely related species, showing its dorsal carina plainly when 

 contracted. 



Geomalacus Bayani, Jousseaume (fig. 27), is a juvenile of 

 this species. 



Section PROLEPIS, Moquin-Tandon, 1855. 



A. HORTENSIS, Fer. . PI. 57, figs. 28-30 ; PL 58, figs. 32-34. 



Small, elongated, rugose, the rugae elongately rounded, shield 

 rather small, finely granulated ; ash or yellowish, darker on the 

 back and middle of the shield,. with a darker zone on either side; 

 tentacles blackish ; margin of foot not usually lineolated. 



Length, 35-50 mill. 



Europe ; Boston, U. S. (introduced). 



The shell-plate is rudimentary or sometimes somewhat de- 

 veloped. 



The synonyms include A. concavus, Brard ; A. leucophaeus, Nor- 

 mand; A.subfuscus, Picard; A. lineolatus^isso; A. circumscriptus, 

 Johnston ; A. variegatus, Turton ; A. fuscus of American authors 

 (fig. 32). 



The varieties include : 



Yar. FASCIATUS, Moquin-Tandon. Grayish ash, fasciated, whitish 

 on the sides, sole and margin of foot yellowish. 



Var. ALPICOLA, Moquin-Tandon. Grayish yellow, the shield 

 yellowish, shield and back distinctly fasciated with brown 

 or black, sole and margin of foot orange-yellow. 



Yar. AUREUS, Lessona. Whitish, yellowish on the back, shield, 

 tail, sole and margin of the foot orange-yellow, dorsal and 

 shield zones obsolete. 



Yar. FUSCATUS, Fer. (fig. 34). Pale brown, the dorsal rugae 

 feeble, elongated, but slightly apparent, separated by grayish 

 sulcations. 



Yar. PELOPHILUS, Mabille. Blackish, with very dark zones, mar- 

 gin of foot bright red. 



Yar. ANTHRAOIUS, Bourg. (fig. 30). Black, with metallic reflec- 

 tions ; sole whitish. 



