UMAX MAXIMUS LINN^US 



221 



triradial slit. Above the mouth are two pairs of tentacles. The 

 posterior tentacles are the longer ones and carry an eye at their 

 end. As we shall see later, the tentacles are provided with special 

 muscles, are retractile and seldom fully extended even in spec- 



Tl 



FIG. 44. Anatomy of Helix pomalia after Cuvier. A, anus; A t, atrium; 

 C, ventricle; Cg, cerebral ganglion; D, intestine; Dr, mucous glands; Ed, 

 albuminous gland; Fl, flagellum; L, liver; M, stomach; Mr, retractor penis; 

 'N, kidney; P, penis; PI, lung; Pr, prostata; Ps, dart sac; RS, sperm recep- 

 tacle; SK, columellar muscle; Sp, salivary gland. 



imens which have been killed with great precaution. The shield 

 or mantle is oval and has an oval opening, the pneumostoma, near 

 its right edge, considerably beyond the middle of the entire 

 length of the mantle. This opening leads to the lung, and near 

 it, in the mantle cavity, lie the anus and the excretory opening 



