POLYGYRA ALBOLABEIS AND LIMAX MAXIMUS 277 



mented several times by placing individuals in various parts of 

 the room, and once in another room. They almost invariably re- 

 turned to the box. 



LIMAX MAXIMUS L. 



The animal has a thick vermiform body, vpith a broad, ribbon- 

 like pedal disk, having very much the appearance of the so-called 

 foot of the P o 1 y g y r a. The mouth, tentacles, etc., are situated 

 as in that genus. The anterior part of the body is rounded. The 

 posterior is acute and dorsally keeled. 



The mantle is situated on the anterior dorsal part of the body, 

 and is somewhat shield-shaped. The anterior margin is rounded; 

 the posterior margin angular. It consists of a thick, fleshy mem- 

 brane. The anterior part is free from the body, and, when the 

 animal contracts, the head is concealed beneath it, the mantle 

 coming down before the head like a mask. The posterior part 

 is not movable. It contains the rudimentary shell, and covers 

 the pulmonary chamber, heart and renal organ. 



The respiratory orifice is situated on the right side of the man- 

 tle, about midway of its length; the mantle being notched or 

 curved around the orifice. 



The genital orifice is situated anteriorly on the right side as in 

 Polygyra. 



The body is divided into two cavities; the smaller containing 

 the pulmonary chamber, the heart, renal organ, and a part of the 

 rectum, the larger containing the digestive and reproductive or- 

 gans, the nerve ganglia and the principal muscles. 



L i m a X differs from Polygyra in that all the organs are 

 contained in the vermiform body, corresponding to the foot of 

 Polygyra, and in being possessed of only a flat, rudimentary 

 shell. Polygyra resembles a L i m a x " with the greater por- 

 tion of the mass squeezed out on the back, and arranged in a 

 turbinate manner", and covered by a shell. 



The integument consists of a thick mucous membrane, with a 

 muscular substratum, as in the foot of P o 1 y g y r a. It is nearly 

 uniformly developed, but is thickest on the mantle, tail and pedal 



