POLYGYRA ALBOLABEIS AXD LIMAX MAXIMDS 289 



its muscles, as well as the muscle of tlie inferior tentacle, are 

 turned forward in order to show a short, broad muscle, which has 

 its origin in the anterior basal part of the body, and is inserted 

 principally in the muscles of theinferior tentacle, but some of the 

 fibers are inserted in the large muscles of the lip (pi. 20, fig. 2, If). 



On the under side of the buccal body, toward the posterior part, 

 are several moderately broad, horizontal bands of muscles, which 

 are partially concealed by overlying longitudinal muscles {10). 

 Bands of muscles are situated on the ventral surface of the 

 buccal body, proceeding from the posteroventral part and diverg- 

 ing to the sides (6). Strong bands of muscles originate in the 

 middle ventral part of the buccal body, and, slightly diverging, 

 are inserted in the anterobasal part of the animal, just under the 

 anterior part of the buccal body (5). A band of muscles is 

 situated on each side of the buccal body, proceeding from the 

 posteroventral to the anterolateral part of the buccal body (7). 



Numerous fibers have their origin in the anterior part of the 

 buccal body, and are inserted in the integument of the mouth. 

 The entire outer walls of the buccal body are composed of mus- 

 cular fibers, both transverse and longitudinal. 



Looking down on the buccal body, the following muscles can 

 be observed: a pair of delicate muscles, one on each side, arising 

 in the inferior posterolateral part of the buccal body, and in- 

 serted in the cephalic integument; another delicate pair arising 

 in the anterolateral part of the buccal body, and inserted in the 

 integument, near the 'base of the inferior tentacles; a pair which 

 proceed laterally from'the anterior basal part of the buccal body, 

 being inserted in th« integument each side of that body. 



The integument or skin of the animal is composed of two layers, 

 the inner of which is composed of interlaced muscular fiber; and 

 the viscera are inclosed by a very thin muscular peritoneum. 

 The first layer is composed of unstriped muscular fibers, ar- 

 ranged transversely, longitudinally and obliquely. 



The peritoneum is composed of muscles arranged transversely 

 and longitudinally, and gives rise to the retractor muscles pre- 

 viously described. 



