224 TERRESTRIAL AIR-BREATHING MOLLUSKS. 



Subgenus PROLEPIS, Moq.-Tand. 



Shield covering an imperfect, rugose, shell-like plate, formed by the aggre- 

 gation of a certain number of calcareous granulations. 



Arion fuscus, Muller. 

 Vol. III. PI. LXIV. Fig. 1. 



Color whitish or light-ashy, sometimes with a tinge of brown, or dark gray- 

 ish ; an obscure, ill-defined dark-colored line or band rises where the mantle 

 meets the base of the eye-peduncles on both sides, and, extending along the whole 

 length of the mantle to its posterior extremity, converges towards the line of 

 the opposite side ; another band, proceeding from under the posterior edge of 

 the mantle, not quite continuous with the above-described line, runs along the 

 sides of the body to its extremity. Body cylindrical, narrow, when extended 

 very much elongated, expanding a little towards its extremity, and ending in a 

 flat and rounded termination ; its upper surface is covered with narrow, oblong, 

 prominent glands, appearing sometimes as if carinated, and arranged in parallel 

 rows, the flanks with elongated tuberculated plates and finer granulations. 

 Head darker than the body, projecting very little beyond the mantle. Eye- 

 peduncles blackish, one eighth the length of the bod}', stout; bulbs translucent; 

 ocular spot at the superior part, black. Tentacles immediately under the eye- 

 peduncles, very short, conical. Mantle small, oval, narrow, commencing just 

 behind tin 1 insertion of the eye-peduncles, less than one third of the length of 

 animal; covered with granulations tending to a vermiform shape. Disk of the 

 foot whitish, without a separate locomotive band, the marginal boundary be- 

 tween it and the body marked by a furrow, projecting beyond the body poste- 

 riorly. Respiratory foramen small, with a cleft to the margin of the mantle. 

 Between the eye-peduncles is a tubercular ridge with furrows on each side. 

 The triangular mucus pore is on the upper surface of the posterior extremity, 

 is very apparent, and has a process of the skin which seems to cover it, and 

 sometimes to project above it. When fully grown, the extreme length is more 

 than 50 mill., the usual length about 25 mill. Internal granulations coarsely 

 united or aggregated into a somewhat ovular, semi-transparent, very granular 

 plate. 



Limax fuscus, Muller, Hist. Term., II. 11 (1774). 



Arion hortensis, Ferussac, Hist., G5, PI. II. Figs. 4, 6; Suppl., p. 96, a (1819). 



— Binney, Bost. Journ. Nat. Hist., IV. 170 (1842); Terr. Moll., II. 27, PI. 



LXIV. Fig. 1; LXV. Fig. 2 (1851). — Leidy, T. M. U. S., I. 249, Fl. II. 



Figs. 1-4 (1851), anat.— UeKay, N. V. .Mull., 23 (1S43). — Reeve, Brit. L. 



& Fr.-W. Moll., 11, Fig. 

 Arion fuscus, Moquin-Tanpon (which see for further foreign synonymes). — W. 



G. Binney, L. >t Fr.-W. Sh., I. 275 (1869). — Tryon, Am. Journ. Conch., III. 



316 (1868). — Gould and Binney, Inv. of Mass., ed. 2, 451 (1870). 



Found in the city of Boston. It is an introduced species common over the 



